The discovery of an atypically shaped Ocotillo (Fouquieria splendens Englem.) at one of my research sites in the foothills of the Organ Mountains in southern New Mexico led to a study to determine whether this was an oddity or a recurring growth form. Ocotillo, the iconic C3, drought-deciduous desert shrub of the Chihuahuan and Sonoran Deserts, typically appears as a multistemmed, spine-laden shrub described as having the appearance of an inverted cone. The new growth form introduced here departed markedly from the V-shape so often associated with Ocotillo. The new growth form, termed Tarantula because its stems are reminiscent of the low, arching legs of the spider, is characterized by having a) a ratio of <0.8 between the maximum height above ground of its longest stem and the maximum length of the same stem, b) an angle between the longest stem and the ground of <50°, and c) stems with a horizontal or downward arching curvature. In 71 transects distributed across four states in the United States and two states in Mexico, 8% of the 6739 Ocotillos sampled were the Tarantula growth form. The mean percentage of Tarantula plants per transect was 8.9%. Six hypotheses are offered as potential explanations for the atypical architecture of the Tarantula growth form. That none of these hypotheses provided a definitive explanation indicates that this visually distinct, widely distributed variant of Fouquieria splendens merits further study. Three avenues of future research are suggested.

Philonotis breutelioides Shevock & Aguero is described as a new endemic moss species restricted to montane and subalpine fen habitats in California from the southern Cascades and Klamath Range south to the southern Sierra Nevada. Molecular data suggests an affinity within the genus Philonotis even though this new species shares morphological character states more frequently observed in the genus Breutelia. Available molecular data suggest distinctiveness of the new species within Philonotis fontana lineage, but they are insufficient to resolve relationships among the taxa in this lineage. Morphologically, Philonotis breutelioides differs from P. fontana by having more narrowly tapered leaves with slightly flexuose apices, leaf base with obvious plications, and elongate thin-walled cells in more numerous rows between costa and margin.

The name Oxalis oregana Nutt. is universally accepted for Redwood Sorrel despite a long history of attempted revisions. One of its many current synonyms, O. smalliana R.Knuth, was proposed over a century ago to describe a primarily Californian wood sorrel species distinguishable from the O. oregana type by flower size and color, but recognition of the taxon faded over time. The present study, however, provides substantial genetic, morphological, and phenological support for the reinstatement of O. smalliana as a separate species. A range-wide genetic study of 16 Redwood Sorrel populations showed divergence of two overlapping lineages at both nuclear (internal transcribed spacer) and chloroplast (psbJ-petA) loci. The southern lineage (ranging from Monterey County, California to Curry County, Oregon) corresponds in distribution and floral characteristics to previous descriptions of O. smalliana. The northern lineage, corresponding to O. oregana, ranges from southern Humboldt County, California to southwestern British Columbia. All O. smalliana specimens were characterized by apparent chloroplast heteroplasmy as evidenced by mixed sequence haplotypes, whereas all O. oregana specimens showed typical single sequence haplotypes. Flower size is generally larger in O. smalliana, and its flowers range in color from white to pink, purple, or blue, whereas O. oregana flowers are only white. Analysis of flower color distribution using more than 1000 images identified as O. oregana in the iNaturalist database showed a transition from southern pigmented flowers to northern white flowers in the Klamath Range of northwestern California and southwestern Oregon that correlated with the transition of the O. smalliana to O. oregana genetic lineages. In two sympatric populations, the white-flowered O. oregana was shown to attain peak flowering a full month later than the purple-flowered morph of O. smalliana. Phylogenetic analysis of internal transcribed spacer sequences showed species-level divergence of O. smalliana relative to O. oregana and other members of Oxalis subsect. Oxalis. Median-joining network analysis of haplotype sequences from all taxa in subsection Oxalis was confounded by probable hybridization and introgression, but provided some evolutionary insights. Divergence of the two species is discussed relative to the Pacific Northwest post-glacial north–south recolonization hypothesis.

Phacelia damnationensis Kierstead et al. (Hydrophyllaceae) is described as a new species from northern California. The new taxon is a large, perennial, multi-stemmed, generally upright, leafy plant growing from a branched woody caudex. Morphologically it appears most closely related to Phacelia Juss. sect. Baretiana Walden & R.Patt., which contains three other species: P. bolanderi A.Gray, P. hydrophylloides Torr. ex A.Gray, and P. procera A.Gray. This new species is currently known from five general areas in the eastern Klamath Ranges of Shasta County, where it occurs on disturbed open, rocky slopes in conifer forest habitat. We describe the morphological and habitat characteristics for P. damnationensis, another in a series of recently discovered vascular plant taxa endemic to the eastern Klamath Ranges and include an updated species key to Phacelia sect. Baretiana.

The amphitropical Trifolium depauperatum Desv. species complex (Fabaceae) is a group of closely related clovers with a disjunct native distribution in Chile and western North America. Based on the most recent treatment by Vincent and Isely in 2012, the species complex includes two species, one of which contains three varieties. Historically, the taxonomy of this species complex has been unstable; therefore, we performed a morphological and molecular analysis from herbarium specimens and fresh tissue to further explore taxonomic delimitations. Multivariate and cluster analyses were performed on the morphological data. Bayesian and Maximum Parsimony phylogenetic analyses were performed on the molecular data. Both data sets support the recognition of four taxa: T. depauperatum var. depauperatum, T. depauperatum var. amplectens (Torr. & A.Gray) Rattan, T. depauperatum var. truncatum (Greene) J.S.Martin ex Isely, and T. hydrophilum Greene. We designate three new lectotypes and one epitype, and provide a key to taxa, synonymy, descriptions, and distributional information for each.

Historical photographs are windows into the past. By comparing historical and modern photographs we can measure change; but how do we find the original camera location to repeat a photograph? Historical, geographic, topographic, and other clues may be used, but we lack a numerical method suitable for any user to find the general location of a historical photograph. We derive a geometric method that can be applied in the field or prior. The method uses measurements of at least three points of reference (POR) in the historical photograph and corresponding geographic locations measured via a compass or on a map. rePhoto, an open-source R package that applies the method and outputs spatial KML files for use with Google Earth, is provided. The geometric method was tested on 20 photographs with known locations and validated by independent users. The effectiveness of the method varied among users, but overall predicted a search area containing the original camera location 70% of the time (the prediction accuracy) and typically predicted search areas 99.5% smaller than the total region evaluated by the method. The method was robust regardless of whether three or four POR were used, and worked well even when POR were more than 30 km away. The proposed method only works for photographs with at least three identifiable geographic POR, thus other methods are illustrated for use more generally. California and the western USA have numerous iconic historical photographs, for which many locations could be found and re-photographed using methods described here.

Several molecular studies in the last 12 yr have made phylogenetic relationships among the nearly 50 species of Allium L. (Alliaceae) in California much better known than details of the plants' biology in the field. Allium jepsonii (Ownbey & Aase ex Traub) S. S. Denison & McNeal, a rare geophyte nearly endemic to Butte County, was studied in the field for 4 yr on a serpentine outcrop at 736 m elevation south of Paradise Lake, to document aspects of growth and reproduction. Plants flowered in late June and early July. Plant density, scape height and numbers of flowers (averaging 26) in the solitary umbels varied significantly through the years, with some variation in these traits related to cumulative rainfall. Each year many flower buds failed to reach anthesis and only 54% of the flowers that opened produced fruits. Bagged flowers produced significantly fewer fruits and seeds than unbagged. Common flower visitors each year included a beefly, Bombylius facialis. Seeds per plant varied by year, with the 4-yr average (200 fruits total) at only 14. Over the years 82% of the fruits made single seeds, with 17% making two and only 0.3% making three. Seeds planted in the field germinated in the winter, with seedlings completing first year growth by June. The cotyledon served as the only photosynthesizing leaf, and elongation of lower parts of the cotyledon pushed the developing bulb into the soil. First year bulbs averaged up to only 2.4 mm maximum diameter, were pearly white, and lacked the dark coats seen on bulbs of flowering individuals.

Orocopia Sage, Salvia greatae Brandegee (Lamiaceae), is an endemic shrub restricted to the Orocopia and Chocolate Mountains within the Colorado Desert of Riverside and Imperial Counties, California. Very little has been published on this species' demographics, distribution, range, ecology, or threats. Generally, habitat for S. greatae has been described as alluvial fans, slopes, and washes between 30–450 m elevation. Our study was designed to focus specifically on documenting threats and describing the demographic patterns of S. greatae populations, as well as establishing a set of baseline data for long-term monitoring. Our surveys, performed in fall and winter of 2019–2020, revealed patterns that differed from the previously documented distribution for this species; we found denser, more expansive populations, and lower mortality rates at even higher elevations, up to 1011 m on steep slopes and rugged terrain. Populations at mid-elevations, 200 to 500 m, had higher mortality rates than high elevation sites. For populations previously considered to be within ‘core habitat’ at elevations below 200 m and within bajadas and alluvial fans, we relocated very few of the populations recorded in the early 1900s, and observed high mortality within those that persisted. Over the gradient studied, we found that the condition of plants significantly increased with elevation, with the highest proportion of vigorous individuals found at higher elevations. Our data indicate that either this species is shifting to higher elevations, or the previously described habitat of S. greatae was biased toward the lower, easily accessible populations, and may have been composed of waifs, as opposed to stable upland populations. Declines noted in mid- and lower-elevation populations are consistent with the effects of drying due to anthropogenic climate change.

An inventory of the vascular plants of Heil Valley Ranch and Hall Ranch in the north foothills of Boulder County was completed during 2017 and 2018, prior to a catastrophic forest fire that severely impacted this area in the fall of 2020. Heil Valley Ranch and Hall Ranch are keystone units of the Boulder County Parks and Open Space system. These large parcels (∼10,000 acres/4047 ha) represent a significant portion of publicly accessible open space in the county and represent an exemplary legacy of land preservation in the region. The biologically diverse foothill landscapes represent the ecotone between the High Plains and the Southern Rocky Mountains. Vital transition zones in the area harbor globally vulnerable and critically imperiled plant associations, the most detailed categorization described by the US National Vegetation Classification (2021). A total of 607 botanical specimens were collected over the course of 39 separate visits. There are 381 species from 82 families of flowering plants represented at the study area, with the greatest diversity occurring in Poaceae and the Asteraceae. Of these, 319 are native, 62 are non-native, and 7 species are of conservation concern. The present study is the first floristic study of these parcels and provides baseline data for future work in the area, as well as information for comparison to floristic works in the broader Front Range foothills region. Together, these studies inform conservation policy at a time when biodiversity is threatened both globally and locally. As the Front Range megaregion rapidly expands in human population, biological inventories will provide critical data to promote the expansion of conservation areas in parallel with urban growth.

We report the second edition of Napa County's vegetation map using California's Manual of Vegetation classification system and aerial imagery from 2016. It covers 2053.54 km2, increases polygon resolution by 23.8%, contains 35,244 polygons, and has 71 landcover types, 60 of which are dominated by natural vegetation. It has an overall error rate of 2.6%, includes canopy density measures for 24 vegetation types, and contains explicit measures of structures in the Wildland Urban Interface (WUI). We compared the new map to the one based on 1993 imagery to ask how effective Napa county's agricultural preservation and conservation regulations have been at preventing conversion of natural vegetation across the county and of agricultural lands within and beyond the county's Agricultural Preserve, established in 1968. We examined net change and change detected using a transition matrix, to seek concealed landcover conversion. The net change shows small increases in Agriculture and Urban extents. However, the transition matrix found substantial Urban expansion into Agriculture, 12.9 km2 overall and 226.9 ha (2.24%) within the Agricultural Preserve; and 30 km2 of agricultural expansion into natural vegetation, including 595 ha of high conservation-value oak woodlands. Due to increased map resolution in the 2016 map, we identified stands of natural vegetation (Oak Woodlands, Grassland, and Chaparral) in areas previously mapped as Agriculture and Urban, as well as Oak Woodlands in areas previously mapped as other vegetation types. Their inclusion in net measures of landcover change substantially obscures actual loss in natural vegetation types and agricultural lands. The net loss for Oak Woodlands is 191 ha, but the transition matrix identifies 782 ha converted to urban or agriculture, which suggests only moderate performance for the county's conservation measures. We also found rates of vegetation change in wildfire-burned areas three times higher than in unburned areas. Conversion of agricultural lands to urban was about 2.3% in the Agricultural Preserve, but 6.3% beyond, showing that county zoning slowed urban expansion. We found changes in spatial resolution and mapping details between vegetation map editions made net measures of landcover change inaccurate, and that transition matrix-analyses provided more accurate accounting and identification of mapping methods errors.