Peteria
Peteria thompsoniae
peteria
spine noded milk vetch, Thompson's peteria
usually erect to ascending, rarely scandent, young growth ± sericeous.
alternate, odd-pinnate;
stipules present, persistent, spinescent;
rachis canaliculate;
petiolate;
leaflets 7–31, usually opposite, rarely alternate, stipels absent, blade margins entire, surfaces glabrate to sericeous or strigose.
congested, usually with more than 2 consecutive flowers reaching anthesis simultaneously, nodes often 20–100+, internodes 1–5(–12) mm;
bracts 5–11 × 0.5–1 mm.
8–100+-flowered, leaf-opposed appearing terminal, racemes;
bracts present, persistent, subulate, sometimes spine-tipped, bracteoles absent.
2–3 mm.
papilionaceous;
calyx tubular, lobes 5;
corolla whitish, sometimes with purplish tinge, 14–22 mm, glabrous;
stamens 10, diadelphous;
anthers basifixed, relatively small, dehiscing longitudinally;
style glabrous, with pollen brush tufted distally;
stigma terminal, capitate, ciliate.
calyx tube (6–)7–11 mm, strigose to sericeous, lobes 7–11 mm;
banner 16–22 mm.
legumes, sessile, laterally compressed, linear [elliptic], elastically dehiscent, glabrous.
40–65 × 6–7 mm.
2–5[–7], cylindric;
hilum apical.
= 8, 9.
= 16, 18.
Peteria
Peteria thompsoniae
Species 4 (2 in the flora).
Peteria is native to the Chihuahuan and Great Basin deserts and nearby regions, and to Mexican pine forests (M. Lavin and M. Sousa S. 1995).
Peteria is distinguished from other temperate herbaceous legume genera by the combination of terminal racemes, spinescent stipels, and cylindric (or at least not strongly compressed) seeds. Plants in Peteria produce edible tubers borne from rhizomes.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Peteria thompsoniae is found in the northeastern Mojave Desert, western Colorado Plateau, Great Basin Desert, and southeastern Columbia Plateau.
Populations of Peteria thompsoniae in northern Arizona (Mohave County) are distinctive in having a longer flowering season (end of April through August), leaflets usually more numerous (25–31), and leaflet surfaces consistently more glabrate and bearing more scattered tannin deposits than in populations from elsewhere. The flowers in these populations have a generally smaller calyx tube (6–7 mm) and a greater number of ovules per ovary (10–12). Populations from southern Utah (Kane and Washington counties) have leaves similar to those of the Arizona populations in that they tend to be more distinctly marked with finely scattered tannin deposits and have glabrate to sparsely strigose surfaces, but leaflet number per leaf is not as consistently high as in the Arizona populations. Populations from eastern Utah (Emery, San Juan, and Wayne counties) are distinct in having narrowly elliptic leaflets with at least adaxial surfaces glabrate (M. Lavin and M. Sousa S. 1995).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaflet blades usually broadly elliptic to orbiculate, rarely narrowly elliptic, 12–21 mm; racemes congested, flowering internodes 1–5(–12) mm, usually with more than 2 consecutive flowers simultaneously at anthesis; banners 16–22 mm; n Arizona, Idaho, Nevada, adjacent California, Utah. | P. thompsoniae |
1. Leaflet blades linear to narrowly elliptic, 3–6(–9) mm; racemes loose, flowering internodes (3–)5–35 mm, rarely with more than 1 flower reaching anthesis at a time; banners 14–16 mm; n Arizona, New Mexico, adjacent sw Colorado, Texas. | P. scoparia |
CA
WildflowerSearch
iNaturalist
USDA Plants Database
PNW Herbaria
