San Marcos Vernal Pool Checklist © W.P. Armstrong, 22 March 2008 Table Of Contents: A Plant Checklist For The San Marcos Vernal Pool Area A Federally Endangered Fairy Shrimp In The Vernal Pools Endangered Plants Of The San Marcos Vernal Pool Area Brodiaeas In San Marcos and On San Clemente Island Does Brodiaea jolonensis Occur In San Diego County? Other Interesting Species In San Marcos Vernal Pool Area (1) Other Interesting Species In San Marcos Vernal Pool Area (2) Until a satisfactory name is applied to these populations, I will refer to southern California populations previously called "Brodiaea jolonensis" as "Coastal BTK" and mountain populations previously called "Brodiaea terrestris ssp. kernensis" as "Montane BTK." The flower color for Brodiaea species on this page is blue-purple to violet. In the following images I have attempted to match their true color;  however, they may appear different on your monitor. 1. Checklist Of Plants In & Around The San Marcos Vernal Pools Vernal pool during heavy rains of January 2005 This site comprises approximately 40 acres of vacant land northeast of the William R. Bradley Park and southwest of Palomar College. Like other vernal pool areas in San Diego County, it is composed of undulating topography with clay hardpan depressions and elevated "mima" mounds. Vernal pools are formed as the water from winter rains accumulates in these impervious clay depressions. The vernal pool area is bounded by S. Pacific Street on the west, S. Las Posas Drive on the east, La Mirada Drive on the north, and Linda Vista Drive on the south. Most of the names in this checklist follow the nomenclature of A Flora of San Diego County by R.M. Beauchamp (1986). They have not been updated with the Jepson Flora of Calif. (1993). Plants with an asterisk * are considered rare or unusual. Family Name Scientific Name Common Name AMARYLLIDACEAE (Liliaceae In The Flora of North America)     1. Bloomeria crocea ssp. crocea     2. Brodiaea filifolia *     3. Coastal BTK (B. terrestris kernensis) *          [Previously listed as B. jolonensis]     4. Brodiaea filifolia x B. orcuttii *     5. Brodiaea filifolia/B. orcuttii x BTK *     6. Brodiaea orcuttii *     7. Dichelostemma capitatum ssp. capitatum     8. Muilla maritima Golden Stars Threadleaf Brodiaea Coastal BTK Mesa Brodiaea Fertile Hybrid Sterile Hybrid Orcutt Brodiaea Wild Hyacinth Common Muilla APIACEAE     9. Eryngium aristulatum var. parishii *   10. Lomatium dasycarpum   11. Sanicula bipinnatifida Coyote Thistle Lace Parsnip Purple Sanicle ASTERACEAE   12. Acroptilon repens   13. Calycadenia tenella   14. Chaetopappa aurea   15. Chamomilla suaveolens   16. Corethrogyne filaginifolia virgata   17. Cotula coronopifolia   18. Cynara cardunculus   19. Filago gallica   20. Gnaphalium chilense   21. Grindelia camporum bracteosum   22. Hedypnois cretica   23. Hesperevax sparsiflora sparsiflora *   24. Hemizonia (Deinandra) fasciculata   25. Holocarpha virgata ssp. elongata   26. Hypochoeris glabra   27. Isocoma veneta vernonioides   28. Lactuca sativa   29. Lasthenia chrysostoma   30. Layia platyglossa campestris   31. Microseris douglasii ssp. platycarpha *   32. Psilocarphus brevissimus *   33. Senecio vulgaris   34. Stebbinsoseris heterocarpa   35. Stylocline gnaphalioides Russian Knapweed Rosin Weed Golden Daisy Pineapple Weed Sand Aster Brass Buttons Artichoke Thistle Narrow-Leaf Filago Cotton-Batting Plant Gum Plant Hedypnois Erect Evax Golden Tarweed Graceful Tarweed Smooth Cat's Ear Isocoma Prickly Lettuce Goldfields Tidy-Tips Small Flower Microseris Dwarf Woollyheads Common Groundsel Brown Puffs Everlasting Nest-Straw BORAGINACEAE   36. Plagiobothrys acanthocarpus   37. Plagiobothrys bracteatus   38. Plagiobothrys californicus Spinefruited Popcorn Popcorn Flower Popcorn Flower BRASSICACEAE   39. Brassica geniculata .   40. Brassica nigra   41. Brassica rapa sylvestris   42. Lepidium lasiocarpum   43. Lepidium nitidum Perennial Mustard Black Mustard Field Mustard Peppergrass Peppergrass CALLITRICHACEAE   44. Callitriche longipedunculata * Water Starwort CAMPANULACEAE   45. Downingia cuspidata * Downingia CARYOPHYLLACEAE   46. Cerastium glomeratum   47. Silene gallica   48. Spergularia bocconii Mouse-Ear Chickweed Windmill Pink Sand Spurrey CHENOPODIACEAE   49. Atriplex semibaccata Australian Saltbush CONVOLVULACEAE   50. Calystegia macrostegia arida   51. Convolvulus arvensis   52. Convolvulus simulans *   53. Cressa truxillensis Morning-Glory Bindweed Clay Bindweed Alkali Weed CRASSULACEAE   54. Crassula aquatica *   55. Crassula erecta Pigmyweed Pigmyweed CYPERACEAE   56. Cyperus eragrostis   57. Eleocharis macrostachya Tall Flatsedge Spike Rush ELATINACEAE   58. Elatine brachysperma * Waterwort EUPHORBIACEAE   59. Euphorbia spathulata * Wart Spurge FABACEAE   60. Lotus hamatus   61. Lotus scoparius scoparius   62. Lupinus bicolor microphyllus   63. Lupinus densiflorus austrocollium   64. Lupinus longifolius   65. Lupinus succulentus   66. Melilotus albus   67. Melilotus indicus   68. Trifolium amplectens   69. Trifolium microcephalum Grab Lotus Deerweed Dwarf Lupine White Lupine Bush Lupine Succulent Lupine White Sweet Clover Yellow Sweet Clover Bladder Clover Maiden Clover GENTIANACEAE   70. Centaurium venustum   71. Erodium botrys   72. Erodium moschatum   73. Erodium obtusiplicatum Canchalagua Long-Beaked Filaree Filaree Long-Beaked Filaree IRIDACEAE   74. Sisyrinchium bellum Blue-Eyed Grass ISOETACEAE   75. Isoetes orcuttii * Quillwort JUNCACEAE   76. Juncus bufonius   77. Juncus dubius Toad Rush Mariposa Rush LAMIACEAE   78. Acanthomintha ilicifolia *   79. Trichostema lanceolatum Thornmint Vinegar Weed LILIACEAE   80. Calochortus splendens   81. Calochortus weedii var. weedii   82. Chlorogalum parviflorum   83. Zygadenus fremontii var. minor Lilac Mariposa Lily Weed's Mariposa Lily Soap Lily Star Lily LYTHRACEAE   84. Lythrum hyssopifolia Loosestrife MARSILEACEAE   85. Pilularia americana * American Pillwort ONAGRACEAE   86. Clarkia purpurea quadrivulnera   87. Gaura sinuata Farewell-To-Spring Butterfly Weed PLANTAGINACEAE   88. Plantago elongata   89. Plantago erecta   90. Plantago pusilla Alkali Plantain California Plantain Plantain POACEAE   81. Aira caryophyllea (See note below)   92. Avena barbata   93. Avena fatua   94. Brachypodium distachyon   95. Bromus diandrus   96. Bromus mollis   97. Bromus rubens   98. Deschampsia danthonioides (See note below)   99. Distichlis spicata 100. Gastridium ventricosum 101. Hordeum murinum leporinum 102. Lolium multiflorum 103. Nasella (Stipa) pulchra 104. Phalaris paradoxa praemorsa 105. Polypogon monspeliensis 106. Vulpia (Festuca) myuros European Hairgrass Slender Wild Oat Wild Oat Purple False-Brome Ripgut Grass Soft Chess Foxtail Chess Slender Hair Grass Saltgrass Nitgrass Foxtail Barley Italian Rye Grass Purple Needlegrass Canary Grass Rabbitfoot Grass Foxtail Fescue POLEMONIACEAE 107. Navarretia fossalis * Navarretia POLYGONACEAE 108. Rumex crispus Curly Dock PRIMULACEAE 109. Anagallis arvensis 110. Centunculus minimus * Scarlet Pimpernel Common Chaffweed SCROPHULARIACEAE 111. Castilleja densiflora ssp. gracilis 112. Linaria canadensis 113. Veronica peregrina xalapensis Owl's Clover Blue Toadflax Veronica SELAGINELLACEAE 114. Selaginella cinerascens * Ashy Spike-Moss TYPHACEAE 115. Typha latifolia Cattail Note: The San Marcos vernal pools contain native hairgrass (Deschampsia danthonioides) and the similar European hairgrass (Aira caryophyllea). When comparing the dried inflorescences of both species in the field, Aira has smaller spikelets (see following image): Comparison of the dried spikelets of Aira caryophyllea and Deschampsia danthonioides in August. Spikelets of Aira caryophyllea are generally less than 4 mm long and narrower. The status of these vernal pools and lovely wildflowers is rather dismal. They are surrounded by buildings in a rapidly growing area zoned for industry. Many of the vernal pools have been intentionally damaged by deep tire ruts and the dumping of debris. Raised topography (mounds) near the vernal pools once supported burrowing owls, but they haven't been seen in this field for years.

The San Diego fairy shrimp (Branchinecta sandiegoensis) is endemic to vernal pools of coastal San Diego County. They have also been recorded from a few localities in Orange County and Baja California. Since most of the vernal pool habitats have been destroyed in southern California due to urbanization and pollution, these tiny crustaceans have been added to the U.S. Fish & Wildlife Service Endangered List in accordance with the Endangered Species Act. Their plight in the San Marcos area is uncertain due to the dumping of debris in the few remaining pools within a rapidly developing industrial zone.

This minute crustacean belongs to the order Anostraca, along with brine shrimp (Artemia). Other related orders of microscopic crustaceans include Cladocera (water fleas), Copepoda (copepods), Ostracoda (seed shrimp), Notostraca (tadpole shrimp), and Conchostraca (clam shrimp). All of these crustaceans are visible to the naked eye, although magnification is required to see details of their body structure. San Diego fairy shrimp are small and transparent, about 5 to 8 mm long.

During winter and early spring, when the ponds collect water, fairy shrimp mature quickly, live as adults, and reproduce. During their mating cycle the male attaches to the female with his clasping antennae. Each female lays hundreds of eggs, which settle into the soft bottom mud and silt as the pool dries out. At this time the adult fairy shrimp die, and plants bordering the pools bloom and set seed for the next winter wet season. During the dormant stage, fairy shrimp survive as embryos within resistant eggs called cysts which are embedded in the desiccated mud sediment. They can remain here for years until sufficient winter rains once again fill the shallow depressions with water. As the vernal pools refill, the mud imbibes water and the cysts hatch, thus releasing a new generation of fairy shrimp into the shallow ponds. Clay hardpan depressions that fill with water during the winter and early spring provide the essential requirements for the survival and perpetuation of fairy shrimp. If vernal pool habitats are destroyed by land developers, the fairy shrimp will not emerge from their dormant cysts and will disappear forever. Unlike many other aquatic crustaceans, they cannot survive in permanent ponds or lakes. They must have the specific requirements of a vernal pool.

The San Marcos variant brodiaea has intermediate characteristics between two other species. One of the most obvious characteristics that indicate possible hybridization is a structure called a staminodium which represents a sterile, nonfunctional stamen. All three species (A, B & C) have three staminodia in the center of the flower, just outside the three yellow stamens. The three staminodia of the variant are intermediate between the conspicuous, petaloid staminodia of Coastal BTK (A) and the slender (filiform), inconspicuous staminodia of B. filifolia (C). The three staminodia of the variant appear strap-shaped and are visible in the center of the flower, just outside the three yellowish stamens. The variant occurs throughout several acres of the property and may have reproduced asexually through cormlets. In May 2005 I visited this same site but did not observe any variants. Instead I found numerous B. filifolia and Coastal BTK. The previous winter and spring was an exceptional year for rainfall in San Diego County and brodiaea populations were plentiful. Unfortunately, the fate of this 40 acre field of brodiaeas is dismal because of the rapid (uncontrolled) urbanization of northern San Diego County. The field is within an industrial zone and is surrounded by buildings.

On the Santa Rosa Plateau of Riverside County populations of BTK exhibit a wide range of variation, including strap-shaped staminodes similar to the San Marcos "variant." Could it be that the San Marcos variant brodiaea is simply a variation within the BTK population?