Early successional wetland habitat is being lost in temperate regions worldwide as a result of changes in disturbance regimes that allow for the establishment and dominance of woody species. This phenomenon is pronounced in fens, which harbor high numbers of special status plant species that require early successional habitat. We investigated the relationship between woody vegetation encroachment and herbaceous species richness within a northern California coastal fen that has been undergoing encroachment by woody vegetation for ca. 80 years. We established 25 transects within the fen and sampled 338 1x1 m plots located at 4-m intervals along transects. At each plot, we recorded the cover of all woody and herbaceous species, as well as litter, thatch, open water, bare soil, and cover of large woody debris. Modeling indicated that woody vegetation cover, height, species richness, litter cover, and distance from the edge of fen were significant predictors of herbaceous species richness. Vegetation sampling indicated that herbaceous species richness declined with increased woody vegetation cover and height and increased litter cover. Canopy closure was found to result in the complete loss of rare plant species and a significant reduction in herbaceous species richness. The results of this study suggest that the re-introduction of disturbance, specifically those that result in the removal of woody vegetation and litter accumulation, is probably essential to maintain herbaceous species diversity and persistence of special status plant species populations in coastal fens.

Two species of Trichostema L. (Ajugoideae, Lamiaceae) from western states need nomenclatural clarification. Trichostema simulatum Jeps. occurs throughout northern California and southern Oregon. It was published by Willis Linn Jepson in his 1925 flora of California citing the type collection as “Klamathon, Copeland 3534, Type”. This is a conflation of the collector's name and the specimen number of the exsiccata West American Plants, in which the type specimen was distributed by C. F. Baker in 1903. Furthermore, an herbarium name, “Trichostema laetum Greene,” appears on most T. simulatum type material. This designation was never published and is a nomen nudum. Trichostema austromontanum F.H.Lewis occurs throughout the mountain ranges of southern California and Baja California. Originally published with two subspecies by Harlan Lewis in 1945, the three taxa have since been determined to be invalidly published because Lewis did not provide a species description, only subspecies descriptions. Herein, we provide a clarification on the type specimens of T. simulatum Jeps. as well as a valid publication of the species name T. austromontanum.

This flora documents the vascular plant diversity of Bird Haven Ranch, a privately owned property with restored wetlands, rice fields, and riparian habitat, located in the Northern Sacramento Valley in eastern Glenn County, CA. Bird Haven Ranch is managed as waterfowl habitat. With increasing acreage of the Sacramento Valley being converted to restored wetland habitat, it is important to understand what plant taxa occur in these areas. We collected specimens documenting 57 families, 159 genera, and 222 vascular plant taxa, of which 58 percent were non-native. Thirty-six of the taxa collected represent new specimen records for Glenn County. Noteworthy collections from this project that add to our knowledge of the native flora of the floor of the north Sacramento Valley include Chlorogalum pomeridianum (DC.) Kunth var. pomeridianum, Perideridia kelloggii (A.Gray) Mathias, and Stuckenia striata (Ruiz & Pav.) Holub. In addition, two special-status plants, Hibiscus lasiocarpos Cav. var. occidentalis (Torr.) A. Gray, and Azolla microphylla Kaulf. were encountered during the survey.

In addition to its high biodiversity, the California Floristic Province contains over 1600 rare taxa, including many endemics restricted to specific soil types and habitats. In the highly urbanized San Francisco Estuary, these narrow endemics face additional limitations from habitat destruction and modification, prompting an interest in their conservation and management. One such taxon, the Federally listed Cirsium hydrophilum (Greene) Jeps. var. hydrophilum (Suisun thistle), is restricted to two or three populations, and may face limitations beyond past habitat loss. In this study, we investigated life history limitations that may contribute to rarity in C. hydrophilum var. hydrophilum. We documented low seed set, high seed predation by beetle larvae, low localized wind dispersal of seeds, and possible inbreeding in smaller patches. Because seeds did not have a stringent germination requirement in the lab, however, restoration or introduction of new populations from seed is possible. Using seeds from larger source populations could increase success of reseeding, as could adding seeds to augment potentially low genetic diversity in existing smaller subpopulations. Further study is needed to understand the ecology of seed predators, the relative importance of seed set and seed germination in the field, and to confirm our potential finding of reduced genetic diversity and inbreeding. Though the causes and consequences of rarity may differ for each species, this study explores several research directions that could be productive for understanding other California endemic Cirsium and rare wetland endemics.

Helianthus devernii T.M.Draper is described as a new endemic species from two small desert spring populations found within Red Rock Canyon National Conservation Area, Clark County, NV. Morphological data and nuclear ribosomal ITS marker data place it in section Ciliares series Pumili. Furthermore, the molecular data allies it most closely to H. pumilus Nutt. Helianthus devernii differs from H. pumilus by its sessile one nerved opposite and alternate leaves, glabrous glaucous stems, and overall smaller heads. The two known populations of H. devernii of approximately 400 individuals occur near the Las Vegas Valley and are threatened by heavy recreational use and exotic plants and animals. A key to the species of Helianthus of Nevada is presented.