Clark, Curtis. 1990. Vascular plants of the undeveloped areas of California State Polytechnic University, Pomona. Crossosoma 16(4):1-7.

Vascular Plants of the Undeveloped Areas of California State Polytechnic University, Pomona

Curtis Clark
Biological Sciences Department
California State Polytechnic University
Pomona CA 91768


Prior to the July, 1989, wildfire, the undeveloped areas of the campus of California State Polytechnic University consisted of coastal sage scrub and adjacent ruderal and otherwise disturbed sites. A total of 107 species of vascular plants had been reported. The species with both the greatest dominance and the highest frequency were Brassica nigra and Artemisia californica.

California State Polytechnic University, Pomona, is located in Los Angeles Co., California, southwest of the junction of the San Bernardino and Orange freeways, on the northeast slopes of the San Jose Hills. The campus encompasses 329 hectares (813 acres), of which more than half consists of buildings, landscaped areas, parking lots, and agricultural fields. The remaining area is designated "undeveloped" for the purposes of this study. It consists primarily of coastal sage scrub, some of which was grazed by cattle and goats as recently as 15 years ago. It also contains ruderal areas and other disturbed sites around the periphery of the developed portion of campus.

In 1986 I began a study of the vegetation of these areas, as a part of a larger study of the biota of the campus. One purpose of the study was to compile a complete list of the vascular plants of the areas. The other was to analyze the composition of the vegetation along seven transects that were also used for studying small mammals, reptiles, and birds.

On July 28, 1989, a wildfire began on the edge of a new housing development in the hills south of campus, and spread over more than 80% of the undeveloped area before it was extinguished. The vegetation studies are continuing, to document the recovery of the area from the fire. The purpose of this paper is to provide an account of the species present before the fire, and their relative importance.


The species list was accumulated from collections and observations of the research assistants involved in the vegetation study, several students in my California Flora course, and myself. Vouchers of all but the commonest species are deposited at CSPU. Nomenclature follows Munz (1974).

The tables of dominance (cover) and frequency of the commonest species were compiled from data taken on the transect lines in the spring of 1987. Each line was marked by posts at 15 m intervals, and vegetation was sampled by estimating the Braun-Blanquet cover class of each species within a circle of 7.5 m radius centered on the post. I calculated relative cover by summing the cover classes for each species and dividing by the sum of all cover classes for all species. I calculated frequency as the percent of stations (individual circles) containing a species (out of 64 total), and relative frequency as this percentage divided by the sum of frequencies for all species.


One hundred nine species of vascular plants were reported for the area (Table 1). Of these, 63 are native to southern California, and 46 are introduced; the introductions are mainly weeds from Mediterranean Europe and Asia. There are no endangered or threatened species. The list is not complete--there are a few other species which have been seen but not firmly documented--but it probably includes more than 90% of all the species that grew in the area.

The four most important species, both in dominance (Table 2) and in frequency (Table 3), were Brassica nigra, Artemisia californica, Centaurea melitensis, and Bromus diandrus; all but the second are Eurasian weeds. However, other typical species of coastal sage scrub, such as Galium angustifolium, Heteromeles arbutifolia, Juglans californica, Lotus scoparius, Malacothamnus fasciculatus, Mimulus longiflorus, Rhamnus ilicifolia, Salvia leucophylla, Salvia mellifera, Sambucus mexicana, and Toxicodendron diversilobum, were among the top 25 species in either dominance or frequency.


Although there is a preponderance of weedy species, at least as judged from the transects, the vegetation of the area is not atypical for coastal sage scrub. With an increase in development in recent years, the undeveloped areas of Cal Poly, along with adjacent areas of Mount San Antonio College, Forest Lawn Memorial Park, and the City of Walnut, constitute the only large area of native vegetation remaining in the San Jose Hills.

A number of new species have been reported since the 1989 fire, some typical fire-followers and others unusual weeds. The fate of these new species and of the existing vegetation will be addressed by the ongoing study.


I thank Judith Bogdanoff-Lord, Gerald Braden, Chris Brady, Nancy Charest, Karen Jensen, Mary Laughlin, Joy Nishida, Cynthia Stubblefield, and Jerry Turney for their assistance. Funding was provided by a grant from the LandLab Research Committee of the Cal Poly Kellogg Unit Foundation.


Munz, P. A. 1974. A flora of southern California. Univ. Calif. Press, Berkeley.

Table 1. Vascular plant species of the undeveloped areas of Cal Poly Pomona. Introduced species are marked with an asterisk.

Class Filicae


   Polypodium californicum Kaulf. - Polypody

Class Angiospermae: Subclass Dicotyledones


   Rhus integrifolia (Nutt.) Benth. & Hook. - Lemonade berry

   Rhus ovata Wats. - Sugarbush

*  Schinus terebinthifolius Raddi  

   Toxicodendron diversilobum (T. & G.) Greene - Poison oak


   Asclepias californica Greene - Milkweed

   Asclepias fascicularis Dcne. - Milkweed

   Sarcostemma cynanchoides Dcne.


*  Ambrosia psilostachya DC. - Western ragweed

   Artemisia californica Less. - California sagebrush

   Baccharis glutinosa Pers. - Mulefat

   Baccharis pilularis DC. - Coyote brush

*  Centaurea melitensis L. - Tocalote

*  Chrysanthemum coronarium L. - Garland

*  Cirsium vulgare (Savi) Ten. - Bull thistle

*  Conyza canadensis (L.) Cronq. - Horseweed

   Eriophyllum confertiflorum (DC.) Gray - Golden-yarrow

   Gnaphalium bicolor Bioletti - Cudweed

   Gnaphalium californicum DC. - Cudweed

   Haplopappus pinifolius Gray - Pine-bush

   Hemizonia ramosissima Benth. - Tarweed

   Heterotheca grandiflora Nutt. - Telegraph weed

*  Osteospermum ecklonis - Freeway daisy

*  Picris echioides L. - Ox tongue

*  Silybum marianum (L.) Gaertn. - Milk thistle

*  Sonchus asper (L.) Hill - Sow thistle

   Stephanomeria virgata - Benth.


   Amsinckia menziesii (Lehm.) Nels. & Macbr. - Fiddleneck

   Cryptantha intermedia (Gray) Greene


*  Brassica geniculata (Desf.) J. Ball

*  Brassica nigra (L.) Koch - Black mustard

*  Lobularia maritima (L.) Desv. - Sweet Alyssum

*  Raphanus raphanistrum L. - Jointed charlock

*  Raphanus sativus L. - Wild radish

*  Sisymbrium irio L. - London-rocket

*  Sisymbrium officinale (L.) Scop. - Hedge-mustard


   Opuntia littoralis (Engelm.) Ckll. - Prickly pear


   Sambucus mexicana Presl. - Elderberry


   Silene laciniata Cav.

*  Stellaria media (L.) Vill. - Common chickweed


*  Salsola iberica Sennen & Pau - Russian-thistle


*  Cistus villosus L. - Rock-rose


   Calystegia macrostegia (Greene) Brummitt - Wild Morning-glory

   Cuscuta ceanothi Behr. - Dodder


   Dudleya lanceolata (Nutt.) Britt. & Rose - Live-forever


   Cucurbita foetidissima HBK. - Calabazilla

   Marah macrocarpus (Greene) Greene - Wild cucumber


   Eremocarpus setigerus (Hook.) Benth. - Dove weed

   Euphorbia albomarginata T. & G. - Rattlesnake weed

   Euphorbia polycarpa Benth.

*  Ricinis communis L. - Castor bean


   Lotus scoparius (Nutt. in T. & G.) - Ottley

   Lupinus bicolor Lindl. - Lupine

   Lupinus polycarpus Greene - Lupine

*  Melilotus indicus (L.) All. - Sweet-clover


   Quercus agrifolia Nee - Coast live-oak


*  Erodium cicutarium (L.) L'Her. - Redstem filaree

*  Erodium moschatum (L.) L'Her.


   Phacelia distans Benth.  Wild-heliotrope

   Phacelia minor (Harv.) Thell.  Wild Canterbury-bell

   Phacelia tanacetifolia Benth.


   Juglans californica Wats. - California walnut


*  Marrubium vulgare L. - Horehound

   Salvia apiana Jeps. - White sage

   Salvia leucophylla Greene

   Salvia mellifera Greene - Black sage

   Trichostema lanceolatum Benth. - Vinegar weed


   Malacothamnus fasciculatus (Nutt.) Greene

*  Malva parviflora L. - Cheeseweed


*  Eucalyptus globulus Labill. - Blue gum


   Mirabilis californica Gray - Wishbone bush


   Zauschneria californica Presl. - California fuchsia


   Eschscholzia californica Cham. - California poppy


   Eriastrum sapphirinum (Eastw.) Mason


   Eriogonum fasciculatum Benth. - California buckwheat

*  Rumex crispus L. - Curly dock


   Claytonia perfoliata Donn. - Miners' lettuce


*  Anagallis arvensis L. - Pimpernel


   Rhamnus ilicifolia Kell.


   Heteromeles arbutifolia M. Roem. - Toyon

   Potentilla glandulosa Lindl. - Cinquefoil


   Galium angustifolium Nutt.

*  Galium aparine L. - Bedstraw


   Salix lasiolepis Benth. - Arroyo willow


   Mimulus longiflorus (Nutt.) Grant - Monkey-flower

   Scrophularia californica C. & S. - Figwort


*  Datura meteloides A. DC. - Jimsonweed

*  Nicotiana glauca Grah. - Tree tobacco

   Solanum douglasii Dunal in DC. - Nightshade


*  Urtica urens L. - Dwarf nettle

Class Angiospermae: Subclass Monocotyledones


   Bloomeria crocea (Torr.) Cov. - Golden stars

   Dichelostemma pulchella (Salisb.) Heller - Blue dicks


   Sisyrinchium bellum Wats. - Blue-eyed grass


   Calochortus catalinae Wats. - Mariposa lily

   Chlorogalum pomeridianum (DC.) Kunth - Soap plant


*  Avena barbata Brot. - Slender wild oat

*  Avena fatua L. - Wild oat

*  Bromus diandrus Roth. - Ripgut grass

*  Bromus mollis L. - Soft chess

*  Bromus rubens L. - Red brome

*  Bromus tectorum L. - Cheatgrass

*  Hordeum glaucum Steud. - Foxtail

*  Lamarckia aurea L. - Goldentop

*  Lolium perenne L. - Ryegrass

*  Phleum pratense L. - Timothy

*  Poa annua L. - Wintergrass

   Stipa coronata Thurb. in Wats. - Needlegrass

*  Triticum aestivum L. - Wheat

Table 2. The dominant plant species on the sampling lines in the undeveloped coastal sage scrub of Cal Poly Pomona.

Species                               Relative Cover

 1. Brassica nigra                      0.1389  

 2. Artemisia californica               0.1239  

 3. Bromus diandrus                     0.0980  

 4. Centaurea melitensis                0.0686  

 5. Bromus rubens                       0.0457  

 6. Salvia mellifera                    0.0457  

 7. Eriogonum fasciculatum              0.0415 

 8. Juglans californica                 0.0403  

 9. Marrubium vulgare                   0.0391  

10. Avena fatua                         0.0343  

11. Sarcostemma cynanchoides            0.0271 

12. Toxicodendron diversilobum          0.0265 

13. Bromus tectorum                     0.0259 

14. Mimulus longiflorus                 0.0210 

15. Sambucus mexicana                   0.0198 

16. Heteromeles arbutifolia             0.0186  

17. Quercus agrifolia                   0.0186 

18. Malacothamnus fasciculatus          0.0168 

19. Bromus mollis                       0.0162 

20. Salvia leucophylla                  0.0144 

21. Brassica geniculata                 0.0132 

22. Stephanomeria virgata               0.0114 

23. Salsola iberica                     0.0102 

24. Rhamnus ilicifolia                  0.0096 

25. Lotus scoparius                     0.0090 

    All other species                   0.0655 

Table 3. The most frequent plant species on the sampling lines in the undeveloped coastal sage scrub of Cal Poly Pomona.

Species                           Frequency (%)  Relative 


   1. Brassica nigra              79.69%          0.1149

   2. Artemisia californica       67.19%          0.0968

   3. Centaurea melitensis        51.56%          0.0743

   4. Bromus diandrus             40.63%          0.0586

   5. Eriogonum fasciculatum      37.50%          0.0541

   6. Marrubium vulgare           31.25%          0.0450

   7. Bromus rubens               25.00%          0.0360

   8. Salvia mellifera            25.00%          0.0360

   9. Sarcostemma cynanchoides    25.00%          0.0360

   10. Brassica geniculata        23.44%          0.0338

   11. Sambucus mexicana          21.88%          0.0315

   12. Avena fatua                20.31%          0.0293

   13. Juglans californica        20.31%          0.0293

   14. Mimulus longiflorus        18.75%          0.0270

   15. Salvia leucophylla         18.75%          0.0270

   16. Toxicodendron diversilobum 17.19%          0.0248 

   17. Heteromeles arbutifolia    14.06%          0.0203

   18. Bromus mollis              12.50%          0.0180

   19. Rhamnus illicifolia        12.50%          0.0180

   20. Stephanomeria virgata      12.50%          0.0180

   21. Bromus tectorum            10.94%          0.0158 

   22. Malacothamnus fasciculatus  9.38%          0.0135

   23. Galium angustifolium        7.81%          0.0113

   24. Lotus scoparius             7.81%          0.0113

   25. Opuntia littoralis          7.81%          0.0113

       All other species                          0.1081

© 1996, 2002 by Curtis Clark

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