PlantaeDB Logo
Login Sign-up

Genus Plagiobothrys in Family Boraginaceae

In botanical taxonomy, a genus (plural genera) is a rank used to group closely related species within a family. In the hierarchy, genus sits below family and above species.

Genera are defined by shared morphological, anatomical, and genetic characteristics (for example, features of flowers, fruits, seeds, or leaves) that indicate a close evolutionary relationship among the species they contain.

Each genus can include one or more species. Examples include Rosa (roses) and Solanum (nightshades, including tomato and eggplant).

Do you wish to read more about plant taxonomy? Click here!

Genus Description

Suggest a correction!

Plagiobothrys is a genus in Boraginaceae, the borage family, with about 60–70 species widely distributed in temperate western North America, extending into Mexico, with scattered species in South America and eastern Asia (Luebert et al., 2016; WFO, 2024). A naturalised Old World element is occasionally recorded (POWO, 2024). The type species of the genus is P. lithocaryus (meinhard Wigand) [sic] according to standard usage (Hasenstab-Lehman & Simpson, 2012).

Diagnostic traits include an annual to short-lived habit, uncinate bristles on stems and leaves, and conspicuous foliage dotted with white or yellowish cystolith inclusions that give many species a speckled appearance. Flowers are borne in bifid scorpioid cymes that become bracteate racemes in fruit; the calyx splits into five unequal lobes in fruit, and the nutlets are four, dorsiventrally compressed, with an attachment scar near the base that is either lateral or subterminal. Morphologically the genus overlaps with Cryptantha, but Plagiobothrys typically retains prominent bracts beneath the nutlets and has nutlet ornamentation ranging from smooth to striate (Hasenstab-Lehman & Simpson, 2012; Luebert et al., 2016).

Diversity concentrates in the Californian Floristic Province, with high local richness in open, seasonally wet habitats such as vernal pools, serpentine outcrops, and gravelly washes; it also occurs at mid-elevations in the western Cordillera and on coastal dunes. A few species extend along the Andes into southern South America, and several are narrow endemics (Luebert et al., 2016; WFO, 2024). The genus displays a suite of adaptive traits to arid to Mediterranean climates, but detailed pollination and dispersal systems remain inadequately resolved in the literature.

Intrinsic biology is dominated by annual life cycles, with opportunistic germination following winter rains. The base chromosome number is frequently reported as x = 11 across Boraginoideae, including Plagiobothrys (Luebert et al., 2016), though counts vary within species.

Taxonomically, Plagiobothrys is nested within tribe Cryptantheae of Boraginaceae (Luebert et al., 2016). Modern phylogenetic work demonstrates that morphological boundaries with Cryptantha are permeable (Hasenstab-Lehman & Simpson, 2012; Nazaire & Hufford, 2012). Subgeneric or sectional classifications are inconsistently applied; some treatments merge the two genera, while others maintain Plagiobothrys with Cryptantha as subgenera or segregates (POWO, 2024; WFO, 2024). These differences reflect unresolved circumscription and ongoing work toward a stable alignment of taxonomy and phylogeny.

Human relevance remains modest. Plagiobothrys is occasionally encountered in horticulture as wildflowers or rock-garden subjects; certain species are reported as weeds in cultivated ground, but none constitute major invasive threats (POWO, 2024).

Conservation status varies across the range. Several narrow endemics face habitat loss, while most wide-ranging taxa remain common, underscoring uneven data coverage and the need for targeted red list assessments (POWO, 2024).

Pick a Species to see its components: