Psorothamnus fremontii var. fremontii

Title

Psorothamnus fremontii var. fremontii

Authors

Rupert C. Barneby

Scientific Name

Psorothamnus fremontii (Torr. ex A.Gray) Barneby var. fremontii

Description

5a.  Psorothamnus fremontii (Torrey) Barneby var. fremontii

(Plate IV)

Leaflets in outline narrowly ovate-elliptic to narrowly obovate, linear-elliptic, or -lanceolate, (2) 3-15 (20) mm long, the larger ones 1.5-2, seldom 3-4 mm wide; n = ± 20 (Spellenberg). — Collections: 52 (i + v.v.).

Stony flats and benches, terraces in canyons, sometimes on talus, rarely in finegrained clays about the edge of desert playas, 270-1350 rarely 1600 m (900- 5330 ft), locally plentiful in the sedimentary ranges of e. Mohave Desert (Old Dad, Providence, Clark, Kingston, Spring and Charleston mountains) of e. San Bernardino County, California and Clark County, Nevada, in Nevada extending feebly north to margins of Amargosa Desert and Frenchman Basin in s. Nye County, e., always n. of Colorado River, through the valley of the Virgin River and affluents to central Washington County, Utah, Grand Wash in n.-w. Mohave County, Arizona, and Pahranagat Valley in Lincoln County, Nevada; disjunctly in the Colorado Basin on Escalante and Colorado rivers in w. Kane and adjoining San Juan counties, Utah, and extreme n. Coconino and Navajo counties, Arizona. — Flowering April to June.—Representative: California. San Bernardino: Wolf 6847, 7086, 10,812, 10,851 (NY, UC); Everett & Balls 23,191 (UC); Alexander 467 (UC). Nevada. Nye: Cronquist & Beatley 8901 (NY); Beatley 8447 (NY). Clark: Clokey 5890 (NY, OKLA, UC, WIS, widely distributed), 7988 (NY, UC); Eastwood & Howell 8930 (CAS, UC); C. L. Hitchcock 3087 (UC). Lincoln: Grullion 39 (UC). Utah. Washington: Eastwood & Howell 1189 (CAS, NY, UC); Maguire 12,314 (NY); Welsh 5272 (NY). Kane: Ripley & Barneby 13,125 (CAS, NY); Harrison 12,127 (NY). San Juan: Welsh 5200 (NY). Arizona. Mohave: Maguire 16,640, 20,596 (NY); Gould 1805 (NY, UC). Navajo: J. Wetherill (from Kayenta) in 1922 (NY). Coconino: A., N., P., & D. Holmgren 15,575 (NY).

Psorothamnus fremontii (Torr.) Barneby, comb. nov., based on Dalea fremontii (John Charles Fremont, 1813-1890) Torr. ex Gray, Mem. Amer. Acad. II, 5: 316. 1854 ("Fremontii").—"Mountains of the Pah-Utah country, S. W. California, on rocks; May, Fremont."— Holotypus, collected May 5, 1844, when Fremont’s party was encamped on Muddy River in s. Clark County, Nevada, NY (herb. Torr.)! isotypus (fragm.), GH! — Parosela fremontii (Torr.) Vail, Bull. Torrey Club 24: 16. 1897. Psorodendron fremontii (Torr.) Rydb., N. Amer. FL 24: 43. 1919.

Dalea johnsoni (Joseph Ellis Johnson, 1817-1882) Wats, in King, Geol. Expl. 40th Parallel, Botany 64. 1871 ("Johnsoni"), — "collected by J. E. Johnson near St. George on the Virgin River, Utah, and also in the same locality by Dr. Palmer, 1870." — Holotypus, GH! —Parosela johnsoni (Wats.) Vail, Bull. Torrey Club 24: 17. 1897. Psorodendron johnsoni (Wats.) Rydb., N. Amer. FL 24: 43. 1919. Parosela fremontii var .johnsoni (Wats.) Jeps., Man. Calif. 558. 1925. Dalea fremontii var .johnsoni (Wats.) Munz, Man. S. Calif. 598, 262, fig. 138. 1935.

An ornamental small shrub with often picturesquely twisted and gnarled branches, silvery- strigulose foliage, and handsome vivid purple flowers. In general appearance it greatly resembles Ps. arborescens var. simplifolius, but it is easily distinguished by the densely glandular pod, the surface of which appears resinous and wrinkled, not sparsely dotted. The populations of sect. Xylodalea found in the Virgin valley near St. George and on the lower Muddy and Meadow Valley rivers in adjoining Clark County, Nevada represent a homogeneous entity, a little variable (as all Psorothamnus) in shape and number of leaflets but otherwise uniform, and it seems certain that Dalea fremontii and D. johnsoni, the types of which came from points about 100 km apart, are exact taxonomic synonyms. In the protologue of D. johnsoni Watson admitted that he had only fragments of genuine D. fremontii for comparison, and the differences that he seemed to find in the leaves and in the emplacement of the ovules have proved insubstantial. The persistence in the literature of the two epithets, in varying combinations, has been due to misconceptions of long standing as to the true nature of the plants originally described. Munz (1959, p. 854), largely following Jepson (1936, p. 332), transmuted supposedly typical D. fremontii into a silvery phase of Ps. arborescens var. minutifolius and reserved the name var. johnsoni for Ps. fremontii sens. lat. of this account, that is including genuine original fremontii of the far eastern Mohave Desert along with the vicariant var. attenuatus. The plant figured by Abrams (1944, fig. 2767) as D. fremontii is ambiguous; according to the accompanying text it should represent Ps. fremontii as here treated, but the spotted pod that accompanies it must be (if correctly drawn) some phase of Ps. arborescens.