Serpentine soils are highly variable environments, but how this variability contributes to maintaining distinct distributions of species at small scales is unclear. We studied parapatric populations of Layia jonesii A. Gray, a rare serpentine endemic, and L. platyglossa (Fisch. & C. A. Mey) A. Gray, a wide-spread species, to understand how edaphic variability and competitive interactions maintain co-occurring, somewhat interfertile, relatives within serpentine environments. We analyzed soil characteristics along a serpentine hillside where L. jonesii and L. platyglossa are restricted to the top and bottom of the hillside, respectively. We used reciprocal transplants to investigate fitness differences on the hillside and a competition experiment to determine if species interactions also restrict the distribution of L. jonesii. The soil analyses showed the top of the hill is drier than the bottom, yet both locations are chemically indistinguishable. Layia platyglossa is better adapted to the edaphic conditions at the bottom of the hillside and L. jonesii is sensitive to competition in the bottom region. Differences in soil water availability, and potentially its effect on the competitive environment, likely contributes to maintaining the distribution of these species. Ionic stress is often cited as a driver of species' distributions within serpentine environments, but our research suggests soil water availability can be an important factor influencing the distribution of interfertile species on serpentine at small scales. Annual variation in precipitation may drive local shifts in species distributions through alteration of the competitive environment.

The Emerald Lake watershed forms a subalpine basin in the upper drainage of the Marble Fork of the Kaweah River in Sequoia National Park, California, with elevations ranging from 2804–3416 m. Five conifer species are present in the basin, with western white pine (Pinus monticola Douglas ex D. Don) as the most dominant species forming 71% of the stems and 82% of basal area censused in 1985 and 1986. Lodgepole pine (Pinus contorta Loudon subsp. murrayana (Grev. & Balf.) Critchf.) was the second most dominant in the watershed as measured by numbers of individuals and basal area, but was almost entirely restricted to mesic bench and wet meadow habitats in the lower elevations of the watershed. Foxtail pine (Pinus balfouriana Grev. & Balf.) comprised 9.5% of the stems and 13.7% of the basal area within the basin, but was largely present on higher north-facing ridgelines where it formed 52% of stems and 65% of basal area. Jeffrey pine (Pinus jeffreyi Grev. & Balf.), and red fir (Abies magnifica A. Murray bis var. critchfieldii Lanner) were present in small numbers in the lower basin in wet meadow and/or mesic granite bench habitats.

Terrestrial chlorophyte algae of the order Trentepohliales are found in humid habitats around the world. Although most diverse and abundant in the tropics, on a global scale the group is nearly cosmopolitan. The most distinctive macroscopic trait of the Trentepohliales is their orange, golden, or red color, which is due to the accumulation of carotenoid pigments. Orange algae of the genus Trentepohlia, the most species-rich genus in the order, can be found growing on trees, rocks, and other substrates along the Pacific Coast of the United States, including the San Francisco Bay region. Perhaps the best known site for these algae is at Point Lobos State Reserve in Carmel, CA. The orange algae at this site are often referred to by California naturalists as “Trentepohlia aurea” or “Trentepohlia aurea var. polycarpa”. Given the challenges in identifying species in this genus and some confusion about nomenclature, we sampled Trentepohlia at Point Lobos and elsewhere in the region to clarify the identity of these algae. We confirm that the Trentepohlia at Point Lobos (and most of the Trentepohlia we sampled at other sites) are T. flava, which was long considered to be a form of T. aurea and was often reported under the heterotypic synonym T. aurea var. polycarpa. Trentepohlia abietina was the only other species recorded and our observations suggest the possibility that in this region the two species may exhibit different substrate preferences (T. flava generalist on many different substrates, T. abietina limited to tree bark).

Common persimmon (Diospyros virginiana L.) is a deciduous tree occurring widely in eastern North America, as far west as Texas. The species is known for producing relatively large, edible fruits that were consumed by Native Americans and by the European colonists who arrived in North America more recently. Because of its fruit production, D. virginiana is broadly planted outside its natural range. Here, I report on five naturalized occurrences of D. virginiana found in the state of California, where the species is not native. In 2016 and 2017, these populations were surveyed and monitored for fruit production. In all populations, mature fruits were found in the autumn, and these fruits were observed to produce viable seeds with filled embryos. Two of the populations have greater than 70 individuals and contain trees at varying levels of maturity. It is not yet known if these populations are the result of asexual reproduction via root sprouting or sexual reproduction via diaspores. However, the production of viable diaspores in all surveyed populations indicates that sexual seed set is occurring. The large size of two stands, one along a creek in Butte County and the other on a river flood plain in Tulare County, suggests that some areas of California might be susceptible to invasion by this species. Future research should try to determine whether recruitment via diaspores is occurring, and whether these seeds are the product of selfing in perfect-flowered plants, or cross fertilization in a population containing both male and female plants, as this would have important implications for the potential invasiveness of this species in the state.