Psorothamnus polydenius (Torr. ex S. Watson) Rydb.
Fabaceae (Pea family)
USDA Symbol: PSPO
"Stiffly angular, divaricately branching shrubs up to 0.4-1 (1.5) m tall, the stout aged stems leafless, the ultimate twigs becoming subspinose after shedding the terminal flower-racemes, the younger stems densely silky-pilosulous with retrorsely subappressed or narrowly descending lustrous hairs up to 1.5-4 mm long, and densely sprinkled with orange blister-glands (often when dried collapsing and saucer-shaped), the foliage pilosulous with loosely ascending, spreading, or subappressed hairs up to 0.25-0.5 mm long, the ashen leaflets pubescent both sides, rarely thinly so and greenish, charged beneath with 1 subapical and 1-3 pairs of livid submarginal glands;." (bibref: 1812).
"Small angularly crooked shrub, the young stems clad in lustrous deflexed hairs and dotted with many red or orange resinous blisters." (bibref: 1812).
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Plant CharacteristicsDuration: Perennial
Leaf Arrangement: Alternate
Size Notes: "Up to 0.4-1 (1.5) m tall." (bibref: 1812).
Leaf: "Leaf-spurs subobsolete up to 1 mm long; stipules fugacious, triangular or subulate, gland-tipped, 0.4-1 mm long; leaves mostly 7-15, rarely 27 mm long, subsessile or shortly petioled, with 3-6 pairs of obovate, obovate-cuneate, or suborbicular, emarginate or retuse flat or loosely folded leaflets 1-4.5 mm long." (bibref: 1812).
Flower: "Peduncles leaf-opposed and terminal to firm tapering branchlets; racemes usually dense but not at all conelike, ovoid to globose or rarely oblong-cylindroid, without petals 10-14 mm diameter, the pilosulous axis finally 3-30 mm long; bracts deciduous, lanceolate or lance-attenuate, pilosulous dorsally, tipped with a subcapitate gland; pedicels 0.2-0.7 (0.8) mm long, charged near base and apex with pairs of small orange glands; calyx 3.9-5.3 (8.3) mm long, pilosulous externally from base upward or only on the teeth, the tube (measured to a lateral sinus) 1.9-2.8 (3) mm long, its ribs becoming prominent but remaining slender, the membranous intervals charged with 1 row of 2-4 (the ventral intervals with up to 6, more scattered) glands, the ventral sinus less deeply recessed than the lateral ones and the orifice therefore oblique, the teeth varying from triangular-acuminate to narrowly lance-acuminate or -caudate, the dorsal one longest, either a little shorter or longer than tube, the ventral pair broadest and shortest: petals marcescent, all opening pink-purple, the banner with a golden eye-spot, this and wings gland-tipped, the keel usually glandless; banner 4.6-6.1 (6.6) mm long, the antrorsely arched claw 2-2.5 (2.8) mm the ovate-cordate, emarginate or retuse blade 3.2-4.2 (4.6) mm long, 2.7-4.6 mm wide; wings 5.4-7 mm long, the claw 1.9-2.5 (2.8) mm, the narrowly oblong, obtuse or truncate-emarginate blade 4-5 (5.4) mm long, 1.5-2.1 mm wide; keel 5.7-8 mm long, the claws (1.9) 2.2-3 mm, the broadly obovate blades (3.7) 4-5.3 mm long, 2.4-3.7 mm wide; androecium 5.2-6.8 mm long, the connective gland-tipped, the anthers (0.55) 0.6-0.8 (1) mm long; ovules 2, collateral." (bibref: 1812).
Fruit: "Pod ± 2.5 mm long, obliquely clavate-obovoid, the style-base lateral, the valves glabrous and hyaline at base, distally rugulose, thinly pilosulous, gross-glandular; seed (seldom seen) 2-2.2 mm long." (bibref: 1812).
Bloom InformationBloom Color: Pink , Yellow , Purple
Bloom Time: May , Jun , Jul , Aug , Sep
Bloom Notes: "Petals marcescent, all opening pink-purple, the banner with a golden eye-spot." (bibref: 1812).
DistributionUSA: CA , NV , UT
Native Distribution: "Great Basin and Mohave Desert, western Nevada, adjoining California, eastward interruptedly to extreme southwestern Utah (P. p. var. polydenius); local in Colorado Basin, east-central Utah (P. p. var. jonesii). ." (bibref: 1812).
Native Habitat: As given for the varieties. (bibref: 1812).
Additional resourcesUSDA: Find Psorothamnus polydenius in USDA Plants
FNA: Find Psorothamnus polydenius in the Flora of North America (if available)
Google: Search Google for Psorothamnus polydenius
MetadataRecord Modified: 2020-12-07
Research By: JAM