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MADRONO

A WEST AMERICAN JOURNAL OF BOTANY

VOLUME XXX 1983

BOARD OF EDITORS

Class of:

1983 Robert W. Cruden, University of Iowa, Iowa City

Duncan M. Porter, Virginia Polytechnic Institute and State University, Blaci<-sburg

1984 Mary E. Barkworth, Utah State University, Logan

Harry D. Thiers, San Francisco State University, San Francisco

1985— Sterling C. Keeley, Whittier College, Whittier, CA Arthur C. Gibson, University of California, Los Angeles

1986 Amy Jean Gilmartin, Washington State University, Pullman Robert A. Schlising, California State University, Chico

1987 J. RzEDOWSKi, Instituto Politecnico Nacional, Mexico Dorothy Douglas, Boise State University, Boise, ID

Editor Christopher Davidson Idaho Botanical Garden, P.O. Box 2140, Boise, ID 83701

Published quarterly by the California Botanical Society, Inc. Life Sciences Building, University of California, Berkeley 94720

Printed by Allen Press, Inc., Lawrence, KS 66044

Reid Moran began botanizing the world when he was very young and had a back-yard Dudleya collection when no more than ten years old. He did his undergraduate work at Stanford and then went on to Cornell to work on Dudleya with Jens Clausen. This was in the early 40s, when some war or another broke out, and Reid joined two of his cohorts as enlistees in the airforce. They ended up in the 15th Airforce flying raids over Jugoslavia. In a stroke of luck, neither good nor bad, Reid got zapped in mission no. 1 and was found by some of Tito's partisans tangled in the top of a tree he was trying to identify. After a lengthy walk he made his way back to safety in Italy and finally flew back to the USA. It should be noted, though, that the return flight was mysteriously routed through a number of North African bases, at each of which Reid managed to nab a few specimens. When discovered back at Cornell, he was in the herbarium pressing some of his acquisitions in full uniform. His well-known, unique sense of humor has affected many of his colleagues, and the noteworthy collection section of this journal has never fully recovered from his famous "I found it there then" contribution.

He finished his PhD at Berkeley with Lincoln Constance and after a brief time as a UC extension instructor, moved to the San Diego Museum of Natural History.

Reid is certainly one of the finest field botanists in the West (sensu lato), and his knowledge of the northwest Baja California flora and that of the islands is unparalleled. We take great pleasure in dedi- cating volume 30 to him.

iii

TABLE OF CONTENTS

Ahart, L. (see Taylor, M. S.) Ardema, D. S. (see Johnson, F. D.) Baker, J. L. (see Davis, C. B.)

Baldwin, B. G., and S. N. Martens, Noteworthy collections of Opuntia bi- gelovii, Mentzelia puberula, Nemacaulis demidata var. gracilis, and Penste- mon pseudospectabilis 258

Barbour, M. G. (see Yoder, V.)

Bartel, J. A. and J. R. Shevock, Dudleya calcicola (Crassulaceae), a new

species from the southern Sierra Nevada 2 10

Becvar, J. E. (see Freeman, C. E.)

Boyd, R. S., Jackrabbit herbivory and creosote bush (Larrea) reproduction 194

(see also under Yoder, V.) Brunsfeld, S., S. Caccio, and D. Henderson, Noteworthy collection of Par-

nassia kotzebuei 64

(see also under Lackschewitz, K.) Brunsfeld, S. J. and F. D. Johnson, Noteworthy collections of Salix Candida,

S. maccalliana, and Eriophorum viridicarinatum 259

Caicco, S., J. CiviLLE, and D. Henderson, Noteworthy collections of Astrag- alus leptaleus and Penstemon procerus 64

(see also under Brunsfeld, S.) Cain, D. J., and H. T. Harvey, Evidence of salinity-induced ecophenic variation

in cordgrass {Spartina foliosa Trin.) 50

Carter, A. M. Review of Imagenes de la flora Quintanarroense (by O. Telez

V.) 198

(see also under Rudd, V. E.) Castagnoli, S., Greg de Nevers, and R. D. Stone, Noteworthy collections

of Brickellia knappiana and Selinocarpus nevadensis 129

Cholewa, a. F. and D. Henderson, Noteworthy collections of Lesquerella

kingii. Astragalus kentrophyta var. jessiae, and Gilia polycladon 63

(see also under Goodrich, S.) Civille, J. (see Caicco, S.)

Cope, E. A., Chemosystematic affinities of a California population of Abies

lasiocarpa 110

Davidson, C, Review of Genera of the western plants (by W. T. Batson) 66

Review of A flora of Waterton Lakes National Park (by Job Kuijt) 197

Davis, C. B., A. G. van der Valk, and J. L. Baker, The role of four macro- phyte species in the removal of nitrogen and phosphorus from nutrient-rich water in a prairie marsh, Iowa 133

DE Nevers, G. (see Castagnoli, S.)

EcKENWALDER, J. E., Review of Atlas of United States trees. Volume 6. Sup- plement (by E. L. Little, Jr.) 131

Ertter, B., Notes on Ivesia rhypara 257

Evert, E. F., A new species of Lomatium (Umbelliferae) from Wyoming 143

EwiNG, A. L. and J. W. Menke, Reproductive potential of Bromus mollis and

Avena barbata under drought conditions 159

Ferren, W. R., Jr. and S. A. Whitmore, Suaeda esteroa (Chenopodiaceae) a

new species from estuaries of southern California and Baja California 181

FORCELLA, F., Review of Basin and range (by J. McPhee) 198

Freeman, C. E., W. H. Reid, and J. E. Becvar, Nectar sugar composition in

some species of Agave (Agavaceae) 153

Fryxell, J. E., A revision of Abutilon sect. Oligocarpae (Malvaceae), including

a new species from Mexico 84

Gill, S. J. and J. D. Mastroguiseppe, Noteworthy collection of Lomatium

tuberosum 259

GiLMARTiN, A. J., A male sterile morph in Lycium jremontii (Solanaceae) from

Baja California Sur 12 7

Goodrich, S., D. Henderson, and A. F. Cholewa, Noteworthy collections of

Astragalus gilviflorns and Hackelia davisii 63

Gray, J. T., Competition for light and a dynamic boundary between chaparral

and coastal sage scrub 43

Harper, K. T., Review of Flora of the Central Wasatch Front, Utah (by L.

Arnow, B. Albee, and A. Wyckoff) 199

Harvey, H. T. (see Cain, D. J.) Harvey, S. J. (see Forcella, F.)

Henderson, D. (see Goodrich, S.; Cholewa, A. F.; Caicco, S.; Brunsfeld, S.;

and Lackschewitz, K.)

Henrickson, J., A new Chihuahuan Desert rose (Rosaceae) 226

Johnson, F. D. and D. S. Ardema, A disjunct population of Ribes sanguineum

(Grossulariaceae) in Idaho 191

Johnson, F. D. and S. J. Brunsfeld, Noteworthy collections of Salix Candida

and Carex flava 259

(see also under Brunsfeld, S. J.)

Kelley, W., Noteworthy collection of Cryptantha mensana 258

Kruckeberg, a. R. and J. L. Morrison, New Streptanthus taxa (Cruciferae)

from California 230

Lackshewitz, K., D. Henderson, and S. Brunsfeld, Noteworthy collection

of Erigeron radicatus 64

Lee, G. J., Noteworthy collection of Phacelia vallicola 129

Lesica, p.. Noteworthy collections of Erigeron flagellaris and Papaver kluanen-

sis 196

Martens, S. N. (see Baldwin, B. G.) Mastroguiseppe, J. D. (see S. J. Gill)

Meinke, R. J., Mimulus hymenophyllus (Scrophulariaceae), a new species from

the Snake River Canyon area of eastern Oregon 147

Menke, J. W. (see Ewing, A. L.) Morrison, J. L. (see Kruckeberg, A. R.)

Nakai, K. M., Is Dudleya parva (Crassulaceae) truly in San Luis Obispo

County? 191

Nesom, G. L., New species of Calochortus (Liliaceae) and Li num (Linaceae) from

northern Mexico 250

Nesom, G. L. and W. A. Weber, A new woolly-headed, monocephalous Erig- eron (Asteraceae) from Montana 245

POHL, R. W., Review of The grasses of Baja California, Mexico (by F. W. Gould

and R. Moran) 197

Porter, D. M., Review of William Robinson 1838-1935. Father of the Enghsh

flower garden (by M. Allen) 261

Powell, A. M., Perityle (Asteraceae), new species and notes 217

Pray, T. R. (see Wagner, W. H., Jr.)

Rees, J. D. (see Vovides, A. P.)

Reid, W. H. (see Freeman, C. E.)

RiGGiNS, R., Noteworthy collection of Pedicularis dudleyi 63

RuDD, V. E. and A. M. Carter, Acacia pacensis (Leguminosae: Mimosoideae),

a new species from Baja California Sur, Mexico 176

Russell, E. W. B., Pollen analysis of past vegetation at Point Reyes National

Seashore, California 1

Sanders, A. C. (see Vasek, F. C.)

Schoolcraft, G. D., Noteworthy collections of Antennaria flagellaris and Cau-

lanthus major 129

Sheikh, M. Y., New taxa of western American Eryngium (Umbelliferae) 93

Shevock, J. R. (see Bartel, J. A.)

Smith, A. R. (see Wagner, W. H., Jr.)

Statement of ownership, management, and circulation for 1982 68

Stewart, J. G., Lemanea (Rhodophyta) in mountain streams of southern CaH-

fornia 255

Stone, R. D. (see CastagnoU, S.)

Strother, J. L., Pionocarpus becomes lostephane (Compositae: HeUantheae): a

synopsis 34

Tavares, I., Review of A field guide to mushrooms and their relatives (by C.

Booth and H. H. Burdsall, Jr.) 66

Taylor, M. S. and L. Ahart, Noteworthy collection of Moenchia erecta 129

TODSEN, T. K. , A new variety of Perityle staurophylla (Asteraceae) from New

Mexico 115

Turner, B. L. and G. Turner, A new gypsophilic species of Galium (Rubiaceae)

from north-central Mexico 31

van der Valk, a. G. (see Davis, C. B.)

Vasek, F. C. and A. C. Sanders, Distribution of Polygala acanthoclada 193

Vinyard, W. C. (see Wharton, R. A., Jr.)

Vovides, a. p. and J. D. Rees, Ceratozamia microstrobila (Zamiaceae), a new

species from San Luis Potosf, Mexico 39

Waggoner, J. P. Ill (see Yeaton, R. I.)

Wagner, W. H., Jr., A. R. Smith, and T. R. Pray, A cliff brake hybrid, Pellaea

bridgesii x mucronata, and its systematic significance 69

Wagner, W. L., Noteworthy collections oi Arenaria stricta, Galium emeryense

subsp. emeryense, and Lepidium oblongum 126

Weber, W. A. (see Nesom, G. L.)

Wells, H., Hybridization and genetic recombination of Circium californicum

and C. occidentale (Asteraceae: Carduceae) 12

Whitmore, S. a. (see Ferren, W. R., Jr.)

Wharton, R. A., Jr. and W. C. Vinyard, Distribution of snow and ice algae

in western North America 201

Woodward, R. A. (see Yoder, V.)

Yeaton, R. I., R. W. Yeaton, and J. P. Waggoner III, Changes in morpho- logical characteristics of Pinus engelmannii over an elevational gradient in Durango, Mexico 168

Yoder, V., M. G. Barbour, R. S. Boyd, and R. A. Woodward, Vegetation of

the Alabama Hills region, Inyo County, California 118

SUPPLEMENT

Buckingham, N. M. and E. L. Tisch, Additions to the native vascular flora of

the Olympic Peninsula, Washington S67

Hunter, K. B. and R. E. Johnson, Alpine flora of the Sweetwater Mountains,

Mono County, California S89

JOKERST, J. D., The vascular plant flora of Table Mountain, Butte County, Cali- fornia Si

Palmer, R., B. L. Corbin, R. Woodward, and M. Barbour, Floristic checklist for the Headwaters Basin area of the North Fork of the American River, Placer County, California S52

SCHAAK, C. G., The alpine vascular flora of Arizona S79

ScHLisiNG, R. A. and E. L. Sanders, Vascular plants of Richvale Vernal Pools,

Butte County, California Sl9

Swearingen, T. a., The vascular flora of the Muddy Mountains, Clark County,

Nevada S31

MADRONO

VOLUME 30, NUMBER 1

JANUARY 1983

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Contents

Pollen Analysis of Past Vegetation at Point Reyes

National Seashore, California,

Emily W. B. Russell Hybridization and Genetic Recombination of Circium

CALIFORNICUM AND C. OCCIDENTALE (ASTERACEAE: CaR- DUCEAE),

Harrington Wells A New Gypsophilic Species of Galium (Rubiaceae) from

North-central Mexico, B. L. Turner and Gayle Turner PioNocARPUs Becomes Iostephane (Compositae: Helian-

THEAE): A Synopsis, John L. Strother Ceratozamia microstrobila (Zamiaceae), a New Species

FROM San Luis PoTosf, Mexico,

Andrew P. Vovides and John D. Rees Competition for Light and a Dynamic Boundary be- tween Chaparral and Coastal Sage Scrub,

John T. Gray

Evidence of Salinity-Induced Ecophenic Variation in

CORDGRASS (SpARTINA FOLIOSA TrIN.),

Daniel J. Cain and H. Thomas Harvey

NOTEWORTHY COLLECTIONS ^ " "

California

Idaho l I i \

Montana-Idaho \^ '

?9B

REVIEWS

ANNOUNCEMENTS

STATEMENT OF OWNERSHIP, MANAGEMENT, AND CIRCULATION

12 31 34

39

43

SO

63 63 63 64

66

65, 67

68

PUBLISHED

QUARTERLY BY THE CALIFORNIA BOTANICAL SOCIETY

Madrono (ISSN 0024-9637) is published quarterly by the California Botanical Society, Inc., and is issued from the office of the Society, Herbarium, Life Sciences Building, University of Cahfornia, Berkeley, CA 94720. Subscription rate: $25 per calendar year. Subscription information on inside back cover. Established 1916. Second-class postage paid at Berkeley, CA, and additional mailing offices. Return requested. Postmaster: Send address changes to Susan Cochrane, California Natural Diversity Data Base, Calif. Dept. of Fish & Game, 1416 9th St. Rm. 1225, Sacramento, CA 95814.

Editor Christopher Davidson Idaho Botanical Garden P.O. Box 2140 Boise, Idaho 83701

Board of Editors Class of:

1982 Dean W. Taylor, University of California, Davis Richard Vogl, California State University, Los Angeles

1983 Robert W. Cruden, University of Iowa, Iowa City

Duncan M. Porter, Virginia Polytechnic Institute and State University, Blacksburg

1984 Mary E. Bark worth, Utah State University, Logan

Harry D. Thiers, San Francisco State University, San Francisco

1985— Sterling C. Keeley, Whittier College, Whittier, CA Arthur C. Gibson, University of Cahfornia, Los Angeles

1986 Amy Jean Gilmartin, Washington State University, Pullman Robert A. Schlising, California State University, Chico

CALIFORNIA BOTANICAL SOCIETY, INC.

Officers for 1982

President: Watson M. Laetsch, Department of Botany,

University of California, Berkeley 94720 First Vice President: Robert Robichaux, Department of Botany,

University of California, Berkeley 94720 Second Vice President: Vesta Hesse, P. O. Box 181,

Boulder Creek, CA 95006 Recording Secretary: Robert W. Patterson, Department of Biology,

San Francisco State University, San Francisco, CA 94132 Corresponding Secretary: Susan Cochrane, California Natural Diversity Data Base,

Calif. Dept. of Fish & Game, 1416 9th St. Rm. 1225, Sacramento, CA 95814 Treasurer: Cherie L. R. Wetzel, Department of Biology,

City College of San Francisco, 50 Phelan Ave., San Francisco, CA 94112

The Council of the California Botanical Society consists of the officers listed above plus the immediate Past President, Robert Ornduff, Department of Botany, Uni- versity of California, Berkeley 94720; the Editor of Madrono; three elected Council Members: Lyman Benson, Box 8011, The Sequoias, 501 Portola Rd., Portola Valley, CA 94025; John M. Tucker, Department of Botany, University of Cahfornia, Davis 95616; Charles F. Quibell, Department of Biological Sciences, Sonoma State Col- lege, Rohnert Park, CA 94928; and a Graduate Student Representative, Christine Bern, Department of Biology, San Francisco State University, San Francisco, CA 94132.

POLLEN ANALYSIS OF PAST VEGETATION AT POINT REYES NATIONAL SEASHORE, CALIFORNIA

Emily W. B. Russell Department of Geology, Rutgers University, Newark, NJ 07102

Abstract

Pollen analysis indicates major vegetational changes near Wildcat Lake, Point Reyes National Seashore, California, in the last millennium. Changes in the relative propor- tions of grass and shrub pollen both before and after colonization imply that the pro- portions of grassland and scrub vegetation were not constant even before European colonization. Near the top of the sediment core the ratio of grass to shrub pollen in- creases. The simultaneous appearance of pollen of introduced plant species allows this level of the diagram to be dated historically at about 1850 A.D. Thus this increase in grasses may be correlated with increased grazing. A shift from abundant Alnus pollen to Myrica and Salix near the bottom of the core is interpreted as the result of a landslide that changed local drainage.

Agricultural and logging practices obscure precolonial vegetational patterns in the New World. Because the patterns are probably caused primarily by interactions of climate, soil and topography, their recon- struction is of considerable interest to ecologists. For example, the Mediterranean type of vegetation that characterizes western California has a fairly short history of active exploitation, generally less than 150 years. Near the coast, extensive short grass pastures are interspersed with shrubby vegetation, occasional small, bunch-grass prairies, and deciduous or coniferous woodlands. The mountain ridges parallel to the coast are mainly forested with Pinus spp. or Pseudotsuga menzie- sii, and many valleys east of these ridges in the northern and north- central parts of the state contain Sequoia sempervirens (Munz and Keck 1959, Ornduff 1974).

Probably the most active cultural exploitations are grazing and ur- banization, which have nearly obliterated the natural vegetation of coastal prairie, dominated by grasses such as Deschampsia holcifor- mis, Calamagrostis nutkaensis and Festuca californica. Grazing has also modified coastal scrub, dominated by shrubs such as Rhus diver- siloba, Ruhus ursinus, Artemisia californica, Baccharis pilularis, Lu- pinus spp., and members of the Rhamnaceae (Howell 1949, Munz and Keck 1959, Barbour et al. 1973, Ornduff 1974, Heady et al. 1977, Grams et al. 1977). The present study concerns the history of an area north of San Francisco, Point Reyes National Seashore.

Previous studies of the past and present coastal vegetation have reached conflicting conclusions about its history, as well as its present

Madrono, Vol. 30, No. 1, pp. 1-11, 28 January 1983

2

MADRONO

[Vol. 30

composition. North of Point Reyes to the Oregon border, Burtt-Davy (1902) found a variety of species, e.g., Erodium moschatum, Bromus rigidus, Hordeum leporinum and Centaurea melitensis, invading pas- ture land in 1900. Based on observations of fenced-off areas, he de- duced that the original forage plants had been perennial bunch grasses, chiefly Danthonia, Stipa and Melica. Wild oats {Avena fatua) and Erodium displaced these very palatable species in the 19th century as grazing pressure increased. Continued grazing led to dominance by Hordeum juhatum, Sitanion hystrix and Bromus mollis by 1900. He saw the presettlement landscape as consisting of prairies and "hard" chaparral of Adenostema fasciculatum, Ceanothus cuneatus and other chaparral species (Burtt-Davy 1902).

At Point Reyes, Baccharis pilularis dominates the coastal scrub, with at least 25% cover (Grams et al. 1977). Floristic differences in the scrub correspond with differences in exposure: on north-facing slopes Polystichum munitum is second in importance, whereas on south- facing slopes Rhamnus californica is second. Grams considered all but one of the sites to be "undisturbed" because they were not being grazed, but he did not outline the history of prior disturbance.

Also at Point Reyes, Elliott and Wehausen (1974) studied distur- bance effects on deep, sandy soil in level, grazed sites. The native bunch-grass Deschampsia caespitosa formed denser cover in a plot ungrazed for six years than in plots continuously grazed by cattle. The growth difference may suggest a shift to prairie vegetation and is interpreted by Elliott and Wehausen as indicating that prairie was the dominant type of vegetation prior to grazing. However, Baccharis pilularis had the second highest cover on the plot, and Rumex ace- tosella, an introduced perennial, ranked fourth. The less heavily grazed plot had more Deschampsia caespitosa than the other, but also more Baccharis pilularis. Their study thus does not give a clear indication of the pre-grazing vegetation, whether it was grassland or scrub.

One hypothesis suggested by these earlier studies (e.g., Burtt-Davy 1902, Elliott and Wehausen 1974, Grams et al. 1977), which is tested here, is that there were major shifts in the proportion of grassland to coastal scrub taxa in the vegetation from pre-Columbian time to the present. This hypothesis would be supported by pollen records indi- cating changes in the ratio of grass to scrub pollen, representing a change in the ratio of prairie to scrub vegetation. The main shrubs to be considered are members of the Asteraceae, e.g., Baccharis pilularis and Artemisia spp., members of the Rhamnaceae, and Rhus diver- siloba. The direction and timing of changes in the poflen record would suggest patterns of succession in the past.

Study Area and Methods

Point Reyes Peninsula, located at 38°N, 123°W, is separated from the mainland by the San Andreas rift zone. The base rock of Creta-

1983] RUSSELL: VEGETATIONAL HISTORY OF PT. REYES 3

ceous granodiorite crops out in the northeastern part of the Peninsula and on the western tip. In most of the area the Miocene Monterey Formation, mainly bentonitic shale, overlies the granodiorite (Gallo- way 1977, Howard 1979). The dip of the Monterey Formation par- allels the slope of the terrain, resulting in extreme landslide suscepti- bility in view of the bentonitic shale, high rainfall on the seaward slopes, and earthquakes (Clague 1969). These landslides have pro- duced a landscape of steep breakaway scarps, large hummocks, and frequent lakes where slumps have dammed stream valleys (see Gal- loway 1977).

The climate is Mediterranean, with wet, cool winters and cool, foggy summers with little precipitation. The mean maximum temper- ature in July is about 16-18°C, whereas the mean minimum temper- ature for the same month is 11°C. Mean maximum temperature in January is 13°C, and the mean minimum is 5-7°C. Mean annual pre- cipitation is 58-67 cm, with almost no rain falling in July-August and the maximum falling in December-February (Elford 1970). Fires in the coastal scrub are common and may alter the vegetation (Wells 1962).

Soil type maps of the Point Reyes Peninsula are not available, but generally the soil in the study area appears to be shaley clay loam over shaley clay, about 50-100 cm deep (Grams et al. 1977). There are also local shale outcrops with very shallow soil.

Wildcat Lake is located near the southwest tip of the Point Reyes National Seashore. A landslide estimated at 70,000-100,000 years b.p. blocked a valley drainage, created the lake, and left a scarp on the lake's northeast side (Fig. 1) (Clague 1969). Later slides of lesser extent left piles of debris, especially on the southeast side of the lake. The ages of these slides have not been determined.

Two sediment cores were taken in 1978 by Roger Byrne and Jeffrey Loux. One, about 50 cm long, was obtained with a 10 cm diameter plastic tube for retrieval of relatively undisturbed shallow samples. The second, 300 cm long, was obtained with a 5 cm diameter Living- stone piston corer, near the site of the first. The coring site was located in a deep part of the lake away from the inlet and outlet at the north- east end (Fig. 1).

Samples were taken from the short core at 1, 20, 30, 35, 40, 45, and 50 cm. From the long core, samples were taken at 25 cm intervals from 50 cm below the surface to 275 cm, plus one at 55 cm. All samples were prepared according to standard procedures for concentrating pol- len and were mounted in silicon oil (Faegri and Iversen 1975). An average of 11,850 Lycopodium spores added to each sample served as a control for comparing relative concentrations of taxa in the sediment. For each sample at least 200 pollen grains were counted at 430 x.

Pollen of species locally associated with wet conditions, Alnus, Sa- li%, Myrica, and Typha, constituted a large proportion of the fossil assemblage in many samples. Changes in these obscured changes in

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60

12 0

Fig. 1. Bathymetric map of Wildcat Lake, including coring site (X) (modified from Clague 1969).

the less common grass and shrub taxa. Lack of radiometric dates for the sediment and major changes in pollen influx made the use of "absolute" pollen diagrams inappropriate. Therefore pollen percents were calculated on two totals, that of the wetland species as a percent of the total and that of the remaining taxa as a percent of these taxa. This differentiation distinguished changes in local drainage patterns

1983]

RUSSELL: VEGETATIONAL HISTORY OF PT. REYES

5

from changes in upland vegetation. Pollen of the wetland species was generally 30% or more of the total, indicating that it was largely locally produced. Upland pollen was blown in from varying distances (Erdt- man 1969, Faegri and Iversen 1975).

To study fire history, the area covered by charcoal particles was determined on the same slides that were used for pollen counts. Only black charcoal in which cellular structure (e.g., spiral wall thickenings or bordered pits) was visible was tallied. The area covered by such a piece was determined using a reticle with unit area = 150 fjim~. The total area of charcoal for each sample was divided by the number of control grains {Lycopodium spores) counted on the same traverses to estimate charcoal concentration. A minimum of 10 control grains, or 10 traverses (at 430 x), was counted at each level.

On 8 April and 2 June 1979, the most obvious taxa with the greatest apparent cover were noted along 12 and 17 km of trails, respectively. On 8 April, the most conspicuous members of the scrub community were Artemisia californica, Lupinus spp., Rhus diversiloba, Pteridi- um aqiiiliniim and Polystichum munitum. Common species noticed blooming were Lupinus spp., Sanicula arctopoides on shallow soil, Eschscholzia californica, Iris douglasii, Ranunculus sp., Heracleum lanatum and Rumex acetosella. In the canyons where streams flowed to the ocean there were small, salt-stunted Pseudotsuga menziesii and some Quercus agrifolia. Higher up above the first range of hills Pseu- dotsuga grew much larger. Near Bass Lake and Lake Ranch, south of Wildcat Lake, were Salix sp., Pseudotsuga menziesii and Alnus rubra.

Near Wildcat Lake, Baccharis pilularis and Rhamnus californica were common. Rumex acetosella and Plantago lanceolata formed most of the vegetation on small paths. Alnus rubra grew thickly along the inlet stream, and Salix sp. at the outlet. Salix also provided dense cover in a gully at the south end of the lake. Trees on the uplands in the vicinity of the lake were Umbellularia californica, Quercus agri- folia and Pseudotsuga menziesii. The only area covered mainly with grasses in the valley around Wildcat Lake was southeast of the large slump southeast of the lake.

Results

Pollen data are given in Fig. 2. Major changes occur between levels 225 and 150 cm in the wetland species. The most salient changes are the decline in Alnus and Typha pollen from 200 cm to 150 cm and the concomitant increase of Myrica and Salix. Notable changes in "non- aquatic" pollen occur at 150-125 cm and around 50-55 cm. Near 150 cm, aquatics appear to stabilize, whereas Sequoia and Artemisia pol- len percentages decline and grass pollen percentage increases. Slightly higher in the core, percent pollen of the Rhamnaceae decreases as that

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RUSSELL: VEGETATIONAL HISTORY OF PT. REYES

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of the Apiaceae increases. Above about SO cm a general increase in Pinus and Quercus pollen is accompanied by a decrease in Asteraceae and possibly in Poaceae. The 50 cm level is also marked by the ap- pearance of the introduced European pasture weeds Plantago lanceo- lata and Rumex acetosella and an occasional grain of Erodium.

The concentration of charcoal is compared with concentration of pollen in Fig. 3. An increase in the concentration of charcoal where a similar increase does not occur in the concentration of pollen probably indicates the occurrence of a fire or fire period. Concomitant increases of pollen and charcoal are caused by changes in sedimentation, which would affect both similarly. Fires are thus indicated at 0, 40, 175, and 225 cm.

The ratio of grass pollen to shrub pollen (Fig. 4) ranges from 1.2:1 to 0.3:1, with a mean of about 0.8:1. The low corresponds with a peak

8

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50

100 -

250 -

0 20 40 60 80 100 120 14 0 160 180 200 220

2

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Fig. 4. Ratio of grass (Poaceae) pollen to scrub (Asteraceae, including Artemisia, Rhamnaceae, Rhus) pollen.

in Myrica pollen at 150 cm. This fluctuating ratio becomes slightly higher (1.0:1) and fluctuates more above 50 cm.

Discussion

The most precise date in the pollen core is the first appearance of pollen of introduced taxa, Rumex acetosella and Plantago lanceolata, at 50 cm (Fig. 2). Historical data place this near 1850 A.D. The core was taken in 1978, indicating a sedimentation rate of 50 cm/128 yr, or 0.39 cm/yr. Extrapolation of this rate to sediment below this point gives a minimum estimate of 1275 A.D. for the age of the sediment. Erosion accelerated by grazing, which increased the input of sediment to the lake, plus compaction at lower levels make this a very conser- vative estimate of the age of the bottom of the core.

The variations in the ratio of grass pollen to shrub pollen (Fig. 4) support the hypothesis that the ratio of grassland to scrub has changed in the past. Fluctuations in the proportion of grassland seem to have occurred before European settlement of the area. It appears likely that the precolonial landscape contained a mixture of prairie and chaparral vegetation, as suggested by Burtt-Davy (1902). The areas studied by Elliott and Wehausen (1974) and Grams et al. (1977) may represent naturally occurring temporal and spatial variation in the mosaic of vegetation.

1983] RUSSELL: VEGETATIONAL HISTORY OF PT. REYES 9

The low ratio of grass to shrub pollen at 150 cm, which corresponds with a peak in Myrica pollen, may be associated with a fire, because Myrica spreads rapidly after fires (Howell 1949). Very high charcoal counts at about 175 cm (Fig. 3) show the possibility of a fire at that level. The fire may have been followed by the spread of Myrica and fire-stimulated scrub species, and a temporary low period of grass growth.

That grass pollen is generally less common than the scrub species cannot, by itself, be taken as evidence that scrub was more common than prairie. Differential production and dispersal of pollen alone may have caused this difference if the scrub species produce more pollen per unit area than the grasses. However, the increased fluctuations in the ratio after European settlement, and the higher grass pollen in some samples, suggest that increased exploitation of the land by graz- ing increased grassland at the expense of shrubs.

The pollen evidence of wetland species (Fig. 2) raises another issue. It appears that sudden changes have occurred in local drainage over the period sampled by this core. These changes, probably associated with landslides, have occurred since the formation of the lake. Above 200 cm the dramatic decrease in alder pollen strongly indicates a re- duction in the habitat of alder, which in this area is generally along streambanks. One may surmise that at this time there was a local landslide or slump that slowed the flow of water in a nearby stream such that the alder no longer had a suitable habitat locally. Then the increased swampy area was invaded by Salix, which presently forms a nearly impenetrable thicket at the outlet of the lake near the north end. The simultaneous decline of Typha pollen could be related to slump filling of the shallow littoral site formerly occupied by Typha. Myrica may have invaded the disturbed habitat formed by the slump debris.

Pseudotsuga, which grows on the ridge east of the lake, is repre- sented in the poUen record with a maximum of six percent. This con- firms Erdtman's (1969) statement that Pseudotsuga pollen has very low powers of dispersal.

After European settlement, the relative amounts of Pinus and Quer- cus pollen increased and, at least at one point, the amount of Sequoia pollen declined sharply. A decline in Asteraceae and Poaceae pollen is associated with the increases in Pinus and Quercus pollen. This might correspond with the type of grazing landscape described by Laperousse in 1786, in which a few trees were left in cattle pastures for shade (Laperousse 1937). The grazed Poaceae and Asteraceae pro- duced little poflen, whereas the trees may have produced more copi- ously than when in a thicker stand. Scrub, consisting largely of Ar- temisia and Rhamnaceae, persisted outside the pastures (Laperousse 1937, Beechey n.d.). The sudden drop in Sequoia pollen and subse- quent recovery above 30 cm probably indicates the heavy logging of

10

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this species in the early 20th century. The peak of Salix pollen at 50 cm may suggest that Judge Shafter, who owned this land in the late 19th century, tried to use Salix as a living fence in places, as did ranchers in the southern part of the state (Fabian 1869).

The vegetation in this area presents a basic pattern in which the non-arboreal pollen remains near 40% of the total. The most important upland taxa are Poaceae, Asteraceae (including Artemisia) and Se- quoia, the latter blown in from a distance. However, shifts in the relative abundances of these pollen taxa indicate changes in the vege- tation during the centuries preceding European settlement in addition to changes caused by European settlement. Causes of the pre-Colum- bian changes are unknown, but topographic disturbances in the area are indicated by sudden shifts in taxa whose distribution is related to changes in local drainage. We may thus see a superposition of topo- graphic disturbance on a system adapted to the local climate, soils and topography.

Acknowledgments

The research for this paper was carried out at the University of Cahfornia, Berkeley, in 1979, while I was a Research Fellow in the Department of Geography. Roger Byrne suggested the topic and provided invaluable logistical assistance, as well as discussion of ideas. Jeffrey Loux collected and processed the sediment as part of term paper research in 1978. Richard T. T. Forman, T. Webb III and G. Batchelder provided helpful comments on earlier versions of this paper.

Literature Cited

Barbour, M. G., R. B. Craig, F. R. Drysdale, and M. T. Ghiselin. 1973. Coast- al ecology: Bodega Head. Univ. California Press, Berkeley.

Beechey, F. W. n.d. An account of a visit to California, 1826-27. Reprint. The Grabhorn Press, CA.

Burtt-Davy, J. 1902. Stock ranges of northwestern California. Notes on the grasses,

forage plants and range conditions. USDA Plant Industry Bull. no. 12. Clague, J. J. 1969. The landslides in the southeast part of Point Reyes National

Seashore. M.A. thesis, Univ. California, Berkeley. Elford, C. R. 1970. The climate of California. In Climates of the States, 2:538-

594. Natl. Oceanic and Atmospheric Admin., US Dept. Commerce. 1974. Elliott, H. W. Ill and J. D. Wehausen. 1974. Vegetational .accession on coastal

rangeland of Point Reyes Peninsula. Madrono 22:231-238. Erdtman, G. 1969. Handbook of palynology. Hafner Publ. Co., NY. Fabian, B. 1869. The agricultural lands of California. H. H. Bancroft and Co., San

Francisco.

Faegri, K. and J. Iversen. 1975. Textbook of pollen analysis. 3rd. ed. Hafner Press, NY.

Galloway, A. J. 1977. Geology of the Point Reyes Peninsula, Marin County, Cal- ifornia. Cal. Div. Mines and Geol. Bull. 202.

Grams, H. J., K. R. McPherson, V. V. King, S. A. MacLeod, and M. G. Barbour. 1977. Northern coastal scrub on Point Reyes Peninsula. Madrdno 24:18-24.

Heady, H. F., T. C. Foin, M. M. Hektner, D. W. Taylor, M. G. Barbour, and W. J. Barry. 1977. Coastal prairie and northern coastal scrub. In M. G. Bar- bour and J. Major, eds., Terrestrial vegetation of California, p. 733-760. Wiley- Interscience, NY.

1983]

RUSSELL: VEGETATIONAL HISTORY OF PT. REYES

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Howard, A. P. 1979. Geologic history of Middle California. Univ. California Press, Berkeley.

Howell, J. T. 1949. Marin flora. Univ. California Press, Berkeley.

Laperousse, J. F. deG. 1937. Le voyage de Laperousse sur les cotes de I'Alaska et de la Californie (1786). Historical Documents, Institut frangais de Washington, Cahier X. Johns Hopkins Press, Baltimore.

MuNZ, P. A. 1959. A California flora. Univ. California Press, Berkeley.

National Park Service. 1976. Natural resources management plan and environ- mental assessment: Point Reyes National Seashore. Washington, DC.

Ornduff, R. 1974. California plant life. Univ. California Press, Berkeley.

Wells, P. V. 1962. Vegetation in relation to geologic substratum and fire in the San Luis Obispo County Quadrangle, California. Ecol. Monogr. 32:79-103.

HYBRIDIZATION AND GENETIC RECOMBINATION OF CIRSIUM CALIFORNICUM AND C. OCCIDENTALE (ASTERACEAE: CARDUCEAE)

Harrington Wells Faculty of Natural Sciences, University of Tulsa, Tulsa, OK 74104

Abstract

Sympatric populations of Cirsium californicum (series Neomexicana) and Cirsium occidentale (series Occidentalia) were studied. The populations occurred as a set of colonies along Happy Canyon Road, Santa Barbara County, California. Morphological data, pollen fertilities, and controlled crosses all support the conclusion that the two taxonomic species studied are one biological species at the Happy Canyon site, that no sterility barriers exist to prevent gene recombination, and that hybrid and recombinant forms compose almost the entire Happy Canyon Cirsium population. However, micro- geographic differentiation of recombinant morphological types was observed to be cor- related to ecological habitats. Protein electrophoretic data support the conclusion that habitat-correlated electrophoretic and morphological phenotypes have a genetic basis rather than having been environmentally induced. The data suggest that the two species have hybridized in the studied population and that differentiation may be occurring along new lines.

The genus Cirsium is in the family Asteraceae, tribe Carduceae (Thistle). Taxonomically, there are between 200 and 250 described species in the genus, of which 34 occur in Washington, Oregon, and California (Howell 1968). Approximately 30 of the West Coast species occur in California (Munz and Keck 1959). The classification of the California species of Cirsium has been changed several times in this century (Jepson 1925, Munz and Keck 1959, Howell 1968, Munz 1974). All of these authors have suggested that the taxon Cirsium is evolu- tionarily complex and in need of further study before its evolutionary dynamics can be completely understood.

Taxonomic division of Cirsium into species is made difficult in part by the presence of morphologically intermediate individuals. Hybrid- ization of Pacific Coast species has been suggested between approxi- mately 23 species pairs involving 19 species (Howell 1968). Hybrid- ization occurs not only between closely related species, but also between some morphologically dissimilar species (C. fontinale and C. querce- torum, and C. brevifolium and C. utahense). It appears that the genus is taxonomically complex and that the difficulty of species delimitation may result from rapid, present-day evolution.

Despite the several revisions of the genus, C. californicum and C. occidentale have always been considered distinct; they have always been placed in separate series and have never been reported to hy-

Madrono, Vol. 30, No. 1, pp. 12-30, 28 January 1983

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bridize. Acceptance of the current ranking of C. californicum and C. occidentale is based on the apparent historical continuity of classifi- cations and agreement of taxonomists (Jepson 1925, Munz and Keck 1959, Howell 1968, Munz 1974).

This study presents data on the interactions of C. californicum and C. occidentale occurring sympatrically in a single well-defined geo- graphic population. Two questions are addressed. First, what degree of biological distinctness has been reached between the species C. californicum and C. occidentale in the study area? Second, what, if any, geographically related genetic differentiation exists in the studied population? Answers to these questions may lead to a greater under- standing of the processes of evolution in nature and ultimately of the phylogeny of Cirsium.

Materials and Methods

Species description. C. californicum branches from the base up- wards. The plants have a strong taproot. Basal leaves develop in a rosette and can be up to 3 dm long and 1 dm wide. They are oblan- ceolate, deeply lobed, and have slender spines. Caulescent leaves are shorter, and have reduced lobes and spininess distally. Leaf blades are glabrescent and green above, and white arachnoid- wooly below. The capitula of C. californicum usually occur solitarily on the ends of long slender peduncles. The heads are up to 6 cm in diameter, and up to 4.5 cm long. The involucre is bowl shaped, making the capit- ulum hemispheric. Phyllaries are spine tipped and spreading above. Flowers are tubular and white, sometimes pink (Table 1).

C. occidentale is an herbaceous, taprooted plant up to 3 m tall. Basal leaves form a rosette up to 8 dm in diameter from which a single thick stem arises. Branching occurs only on the upper stem and forms the inflorescence. Leaves are purple to reddish with