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Ashes To Wildflowers: Image Page 8
Post-Burn Plant Succession Following Comet Fire East Of Palomar College,
Including Remarkable Leaf-Litter Ant, Other Insects, Spiders & Rattlesnakes
Compiled by W.P. Armstrong During Winter & Spring Months Of 2021
Plant names follow Checklist Of The Vascular Plants Of San Diego County by
Jon Rebman & Michael Simpson, San Diego Natural History Museum, 2006.

  A Few Coastal Sage Scrub Images From Summer  

This beautiful lily blooms in late spring & early summer in the hills of coastal sage scrub bordering Palomar College. This image was taken on nearby Owens Peak in June, 2015.


Cooper's Hawk hunting in coastal sage scrub. Flowers in background are wild buckwheat (Eriogonum fasciculatum var. fasciculatum), a dominant shrub in this plant community. Image taken 8 July 2021 in nearby Twin Oaks Valley.


Another Summer Wildflower In Hills East Of Palomar College
Asteraceae: Deinandra (Hemizonia) fasciculata (Tarweed)

Back in the late 1990s, Bruce Baldwin, now of the Jepson Herbarium and Department of Integrative Biology at UC Berkeley, noticed common leaf characteristics between the California tarweeds and the Hawaiian silverswords. Through his research, he determined that a California tarweed gave rise to the exotic looking silverswords of Hawaii. About 30 Hawaiian species in three different genera form the "Silver Sword Alliance," a truly remarkable example of adaptive radiation. According to S. Carlquist, B.G. Baldwin and G.D. Carr (2003), three California perennial tarweeds of the Madiinae are closely related to the Silver Sword Alliance, including Carlquistia muirii of Monterey County, Anisocarpus scabridus of Shasta County and other northern California Counties, and Kyhosia bolanderi of the high northern and eastern California mountains. Early crosses between some tarweeds and the Hawaiian silverswords were fruitless, but when Bruce Baldwin crossed a Hawaiian silversword with each of these three species, hybrids were produced and their close relationship was confirmed. These taxonomic affinities are based on chromosome comparisons, hybridization studies and comparative chloroplast DNA. The Silver Sword Alliance apparently evolved from an ancestral, self-pollinating, California tarweed that colonized these islands millions of years ago. Presumably the ancestral tarweed seeds reached the Hawaiian islands by drifting or rafting in the ocean currents. Extensive research on the silver sword and its relatives by Dr. Gerald Carr at the University of Hawaii (and others) indicates a close genetic and biochemical affinity with the tarweed subtribe (Madiinae) of the sunflower tribe (Heliantheae) of the sunflower family (Asteraceae). It is quite remarkable how an ancestral tarweed got to the Hawaiian islands and gave rise to such a striking group of plants known as the Silver Sword Alliance.

There are several indigenous genera of native tarweeds that are able to compete with aggressive naturalized weeds in disturbed areas of California. For example, the genus Deinandra (Hemizonia) is widespread in coastal foothills and valleys of California, including many annuals and a few perennial species. These California tarweeds are generally small plants with sticky, aromatic foliage. They are adapted to a Mediterranean climate with dry, hot summers. One common annual species (D. fasciculata) is fairly common in San Diego County in heavy, clay soils. It blooms during the summer months when the ground is so hard and dry that it is difficult to penetrate with a shovel. In fact, it actually grows like an aggressive weed in disturbed areas near Palomar College, and even colonizes disturbed ground which has been bulldozed.

  Images Of The Hawaiian Silver Sword Alliance  

References About The Sunflower Family

  1. Carlquist, S., B.G. Baldwin, and G.D. Carr, Editors. 2003. Tarweeds & Silverswords: Evolution of the Madiinae (Asteraceae). Missouri Botanical Garden Press, St. Louis, Missouri.

  2. Carlquist, S. 1980. Hawaii: A Natural History. Pacific Tropical Botanical Garden, Lawai, Kauai, Hawaii.

  3. Jansen, D.H. (Editor). 1983. Costa Rican Natural History. The University of Chicago Press, Chicago, Illinois.

  4. Kepler, A.K. 1984. Hawaiian Heritage Plants. Oriental Publishing Company, Honolulu, Hawaii.

  5. Rock, J.F. 1974. The Indigenous Trees of the Hawaiian Islands. Pacific Tropical Botanical Gardens, Kauai, Hawaii. Charles E. Tuttle Company, Rutland Vermont.

  6. Wagener, W.L., D.R. Herbst and S.H. Sohmer. 1999. Manual of the Flowering Plants of Hawaii. Volumes 1 & 2 (Revised Edition). Bishop Museum Press, Honolulu, Oahu, Hawaii.

  7. Walters, D.R. and D.J. Keil. 1996. Vascular Plant Taxonomy. (Fourth Edition). Kendall/Hunt Publishing Co., Dubuque, Iowa.


Comet Fire Post-Burn Update: 21 October 2021

The following 2 images of the native rush-rose (Helianthemum scoparium) in the rock-rose family (Cistaceae) were taken in the burned area on 21 Oct. 2021. In its leafless stage of late summer and fall, it superficially resembles a rush (Juncus) . It is a very common fire-follower along with bush mallow (Malacothamnus fasciculatus). I did not encounter rush-rose during my spring survey of these post-burn hillsides.

This species is listed as Crocanthemum scoparium in Kew Plants of the World Online, and Helianthemum scoparium is listed as a synonym. Kew also lists the genus Helianthemum as a synonym of Helianthus in the sunflower family (Asteraceae). I was using my Jepson Flora (2nd Edition, 2012) and Vascular Plants of San Diego County (4th Edition, 2006); however, according to the updated, online Jepson eFlora, the correct genus is Crocanthemum.

Rush-rose (Helianthemum scoparium) in its drought dormant phase. It is growing
among dense population of the bush mallow (Malacothamnus fasciculatus).
Rush-rose (Helianthemum scoparium) in its drought dormant phase.

The following image of the native rush-rose shows why it is referred to as a rose! It is also called "rock-rose" in some references. It belongs to the same plant family as cultivated, drought resistant rock-rose shrubs (Cistus species). In fact, the flower resembles a rose because of the numerous stamens with 5 sepals and 5 petals. Although it superficially resembles the rose family (Rosaceae), the stamens are attached to the base of the ovary and not on a hypanthium as in the Rosaceae. There was a beautiful hybrid rock rose in the Palomar College Arboretum and a lovely naturalized hybrid on the north side of nearby Owens Peak.

Rush-rose (Helianthemum scoparium) in full bloom resembling a rose.

Rock rose in Palomar Arboretum (Cistus x purpureus), a hybrid
between 2 Mediterranean species, C. ladanifer and C. creticus.


Naturalized Rock-Rose On North Side Of Owens Peak

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