Following disturbance, seed pre-treatment is essential for re-establishing many species with low germination rates. However, some seeds, such as those from chaparral plants, do not respond to common horticultural treatments. Instead, methods that mimic chaparral's natural succession cues (e.g., fire) should be used to improve seed germination and restoration success. Fire effects, such as heat, charate, leachate, smoke, and/or liquid smoke, are effective in breaking long-term seed dormancy in many chaparral plants. The challenge is to break seed dormancy in a cost- and time-efficient manner that can be used in large-scale restoration projects. Results of our study show that short-term exposure (10 minutes to one hour) to liquid smoke and/or heat enhances seed germination of Adenostoma fasciculatum Hook. & Arn. (chamise), Ceanothus cuneatus (Hook.) Nutt. (buckbrush), and Salvia mellifera Greene (black sage). Chamise seeds treated with liquid smoke have the greatest percent increase of seed germination odds: 394%, from the control (P < 0.000). Buckbrush seeds treated with liquid smoke and heat have the greatest percent increase of seed germination odds: 953%, from the control (P < 0.000). Black sage seeds treated with heat have the greatest percent increase of seed germination odds: 354%, from the control (P < 0.000). Implementing these procedures in restoration may reduce the seed costs of certain species by nearly 90%.

Native plants in most California ecosystems are adapted to fire, but altered fire regimes and disturbance from firefighting activity, such as the construction of firebreaks or firelines, can change plant community composition and the ratio of native to nonnative species. In October 2007, a wildfire burned 710 acres through a chaparral/grassland mosaic on an ecological reserve, providing an opportunity to quantify fire and fireline disturbance impacts on native and nonnative species under differing disturbance conditions. In the spring of 2012 we sampled the plant community in three adjacent sites, focusing on Centaurea melitensis, which is a common nonnative invader after fire in California chaparral. The first site was burned and bulldozed, the second site was burned but not bulldozed, and the third site was not burned or bulldozed. The first site had also been sampled in the spring of 2008. After four years within the burned fireline site, the mean relative cover of C. melitensis decreased from 72% to 28%, but its density increased, and there were increases in the covers of nonnative annual grasses, litter, and native plants. Among the three sites in 2012, both of the burned sites had higher density and cover of C. melitensis and lower relative cover of annual grasses than the unburned site. The only site with notable native perennial presence was the burned fireline. The results of our study suggest that the recruitment of C. melitensis and some native species is promoted by fire. In the absence of additional disturbance by firelines, persistence of these taxa is limited by competition from nonnative annual grasses.

Principal component analyses (PCA) and principal coordinate analyses (PCoA) suggest that Senegalia berlandieri (Benth.) Britton & Rose hybridizes with S. crassifolia (A. Gray) Britton & Rose, the resulting hybrid being S. × anisophylla (S. Watson) Britton & Rose. This uncommon hybrid is reported from the states of Coahuila, Durango, and San Luis Potosí, Mexico. In addition, PCA and PCoA suggest that S. berlandieri hybridizes with S. reniformis (Benth.) Britton & Rose. The resulting hybrid, S. berlandieri × reniformis, also is infrequent, being restricted to the state of Querétaro, Mexico. The morphological features of both probable F₁-hybrids are highly variable. The backcrosses to each respective parent were also examined. The hybrid between S. berlandieri and S. reniformis (Senegalia × zamudii Seigler, Ebinger, & Glass) is described.

Studies of the Monotropoideae (monotropes; Ericaceae), a monophyletic group of non-photosynthetic, mycoheterotrophic, and often rare or endangered plants, have been limited by the inability to propagate them. Monotropes associate with specific fungal hosts, and the only previously known method of seed germination was induction by host fungi or closely related fungi. In order to overcome very low monotrope seed germination rates and to facilitate further study and conservation efforts, we developed a method using gibberellic acid (GA) to induce asymbiotic germination. Pterospora andromedea Nutt. (Monotropoideae, Ericaceae) and Sarcodes sanguinea Torr. (Monotropoideae, Ericaceae) seeds from California were exposed to their fungal symbiont or to agarose infused with 0–1 mM GA and then scored for germination. Continuous exposure to 0.5 mM GA for two months induced 75% P. andromedea germination, compared to only 21% with its host fungus, Rhizopogon salebrosus A.H. Sm. (Basidiomycota). Even short GA exposure (one or three days) significantly enhanced germination (69% and 90%, respectively). The highest germination rate was observed with exposure to 0.5 mM GA for three or 14 d. The closely related S. sanguinea required a three-month exposure to GA and even then produced far lower germination rates (∼1%). Nevertheless, this is the only known method of inducing monotrope germination without the presence of a specific fungal symbiont. In the case of P. andromedea, exogenous GA stimulates germination at rates far higher than that achieved with its fungal symbiont. Application of GA to induce monotrope germination may be used to examine the early stages of mycoheterotroph development, to improve assays for seed viability, and potentially to aid conservation efforts.

We assessed the vulnerability to climate change of 156 rare plant species. The species were selected from the 1625 rare species in California to comprise eight rarity types, classified according to range size, population size, and habitat specificity. For each of the 156 species, we first assigned a climate change vulnerability score using life history attributes and species distribution models, as specified by the Climate Change Vulnerability Index (CCVI) of NatureServe. The resulting CCVI scores were extremely vulnerable (n  =  2), highly vulnerable (n  =  40), moderately vulnerable (n  =  57), presumed stable (n  =  32), increase likely (n  =  16), and insufficient evidence (n  =  9). Piperia yadonii Rand, Morgan & Ackerman and Mimulus purpureus A. L. Grant were the species scored as extremely vulnerable. There was no correlation of the CCVI scores with rarity type, suggesting that climate change vulnerability cannot be inferred by simple categorizations based on geographic range and habitat preference. Second, we conducted a follow-up species distribution model sensitivity analysis that showed that the modeling results were highly dependent upon both model algorithm and choice of predictor variables. However, 60 of the 156 species were predicted to have declines in climatic suitability, regardless of modeling technique. Third, as an independent assessment of vulnerability, we calculated the topographic complexity around known occurrences of each species. Species in topographically dissected landscapes may be less vulnerable to climate change because they can find suitable climates locally as climate changes. We found that topographic complexity varied substantially, even within a single CCVI score level, and therefore provides unique information on vulnerability. Our results can be used to guide monitoring, management, and conservation plans for rare plant species.

The Lomatium triternatum complex is widespread in the Columbia River Basin. Lomatium triternatum (Pursh) J. M. Coult. & Rose var. triternatum and L. triternatum (Pursh) J. M. Coult. & Rose var. anomalum (M. E. Jones ex J. M. Coult. & Rose) Mathias are sympatric throughout much of their range and are reported to have similar fruit but different leaves. Plants of the two varieties repeatedly occur within 5–30 m of each other at an unusual site in northwest Montana, USA. We collected data on leaf and fruit morphological characters and habitat associations at this site to help address whether the proper taxonomic rank for these two taxa should be revised. Terminal leaflet shape and specific leaf area differed between the two varieties with little or no overlap. Fruit mericarp length and width also differed between the two varieties. These patterns are not consistent with treating L. triternatum var. triternatum and L. triternatum var. anomalum as sympatric, interbreeding, conspecific taxa. The two varieties of L. triternatum also occurred in different plant communities in spite of growing in close proximity: var. anomalum occurs with tall, leafy forbs, while var. triternatum is associated with xeric-adapted bunchgrasses and cushion-forming forbs. We conclude that the two varieties are better recognized as separate species.

Datura arenicola, a new species originally collected and named by H. S. Gentry, is documented from Baja California Sur, Mexico. Following a study of Datura (Solanaceae) in western Mexico, the new species is placed in the new section Discola, with section Dutra emended and the revision of section Ceratocaulis proposed. Datura arenicola is found at elevations of 75–100 m on the eastern Vizcaíno Desert, and is characterized by a short basal stem, decumbent habit, pubescent lobulate leaf, prismatic calyx, violet flower, and pendant globose spiny fruit, dehiscent in four parts. The new species is known from a very limited geographical area, 12 km across the range. A description of the Datura on the southern Baja California peninsula and a key to the comparable species are provided.

Datura arenicola, una nueva especie recogida y nombrada originalmente por H. S. Gentry, es documentada de Baja California Sur, México. Después de un estudio de la Datura (Solanaceae) en México occidental, la nueva especie se sitúa en la nueva sección Discola, con la sección Dutra enmendada y la revisión propuesta de la sección Ceratocaulis. Datura arenicola se encuentra en las elevaciones de 75–100 metros en el este del desierto de Vizcaíno, y se caracteriza por un tallo básico corto, un hábito recostado, una hoja lobulada pubescente, un cáliz prismático, una flor violeta, y una fruta espinosa globosa pendiente, dehiscente en cuatro porciones. La nueva especie se conoce en un área geográfica muy limitada de 12 kilómetros a través de la gama. Una descripción de la Datura en al sur de la península de Baja California y una clave de las especies comparables se proveen.

Limnanthes douglasii R. Br. subsp. ornduffii E. G. Buxton (Limnanthaceae), a narrowly endemic meadowfoam from Moss Beach (Half Moon Bay) in San Mateo County, California, is described. Though it shares the morphological trait of being tetramerous with Limnanthes macounii Trel., an endemic species in British Columbia, Canada, it is not a sister taxon to L. macounii based on molecular sequence evidence. L. douglasii subsp. ornduffii appears in an unresolved group with other L. douglasii populations/subspecies. Molecular data coupled with morphological distinctiveness and geographical endemism provide a credible basis for recognizing the Moss Beach population as a L. douglasii subspecies. Data suggest that tetramerism in the genus has arisen more than once.

The fern-leaved monkeyflower, Mimulus filicifolius (Phrymaceae, Section Simiolus), is a new species described from the northwestern corner of the Sierra Nevada of California. The new taxon is differentiated from close relatives of Mimulus L. (M. laciniatus Gray and M. guttatus DC.) mostly by having many finely divided, bi-pinnately compound leaves. Mimulus filicifolius occurs mainly within ephemeral seeps of rock outcrops, where it occupies similar habitats to M. laciniatus, which occurs farther south in the Sierra Nevada. Mimulus filicifolius appears to be highly geographically restricted, and is currently known only from Butte and Plumas Counties within the Plumas National Forest. It therefore merits strong conservation consideration.

Polemonium eddyense Stubbs, sp. nov. (Polemoniaceae) is a localized endemic from Mt. Eddy in the Klamath Ranges of northern California. The new species resembles P. chartaceum H. Mason from the White and Sweetwater mountains. It is distinct from P. chartaceum in having round, rather than acuminate calyx lobes, heavier seeds, longer styles, and greater stigma exsertion. Polemonium pulcherrimum Hooker var. shastense (Eastw.) Stubbs, is a new combination from Mt. Shasta and Mt. Lassen. It differs from other varieties of P. pulcherrimum in corolla color, as well as geography, elevation, stature, and pubescence.

Lagophylla diabolensis is a new hare-leaf from the southern Diablo Range of Fresno, Monterey, and San Benito counties, California. Plants of the Diablo Range hare-leaf were previously included within L. dichotoma, which is treated here in a restricted sense to comprise plants from the Sierra Nevada foothills and eastern Great Central Valley. Lagophylla diabolensis differs morphologically from L. dichotoma by having consistently glandular distal foliage (glands clear to dark-purple), narrower cauline leaves, generally uniformly tawny stems, and smaller heads. The taxonomic significance of those morphological differences is corroborated by other evidence that L. diabolensis is more closely related to the widespread L. ramosissima than to L. dichotoma sensu stricto. The Diablo Range hare-leaf occurs as scattered colonies, often in clayey soils of grassy openings in oak-pine woodland below 1100 m elevation. Extreme rarity and paucity of recent collections of L. diabolensis and L. dichotoma in the current sense indicates that both species warrant conservation concern.