Dalea compacta var. pubescens

Title

Dalea compacta var. pubescens

Authors

Rupert C. Barneby

Scientific Name

Dalea compacta var. pubescens (A.Gray) Barneby

Description

47b. Dalea compacta Sprengel var. pubescens (Gray) Barneby

(Plate LVIII)

Stems commonly erect or ascending at angles of 45-70°, but sometimes diffuse; leaflets mostly less than 3 mm wide; 2n = 14 (Wemple, 1970, p. 12); otherwise as in key. — Collections: 37 (v).

Stony limestone hills, live-oak savannahs, and mesquite prairie, mostly below 450 m, widespread and locally abundant over the hill country of e. Texas, n. to both banks of Red River in s.-centr. Oklahoma and adjacent Texas, s. to Balcones Escarpment, w. to Eastland and Kerr counties, s.-e. on the Gulf Coastal prairies to Jackson County; isolated outliers near Amarillo in the Texas Panhandle, in Caddo Parish, Louisiana, and (according to Wemple, 1. c.) in trans-Pecos Texas and the Rio Grande valley are perhaps introduced or mistakenly labelled; cf. Wemple, 1970, map — Representative: Oklahoma: Wemple 402 (NY). Texas: E. Hall 139 (NY); Corv 53,308 (NY, UC), 53,336 (NY); Tracy 8041 (NY, UC); Barneby 14,491 (CAS, F, I A, MICH, NY, UC, US), 14,500 (IA, NY, US), 14,503 (CAS, NY); A. Heller 1857 (NY, OKLA, UC, US, WIS); Wemple 234 (NY).

Dalea compacta Sprengel var. pubescens (Gray) Barneby, comb. nov., based on Petalostemon violaceum var.pubescens (hairy) Gray, Pl. Wright. 1: 46. 1852, p. 9., quoad basonym. Scheeleanum et pl. tex. Wrightianam, exclus. "Pl. Fendl. 33" plantisque ibi citatis.—Lectoholotypus (Heller, 1901, 1. c. infra): Wright from Austin, Texas [no. 117], GH!—Petalostemon pubescens (Gray) A. Hell., Muhlenbergia 1: 28. 1901 (Aug), homon. posterior (non P. pubescens A. Nels., 1901, Jun). P. purpureum var. pubescens (Gray) Boivin, Nat. Canad. 87: 43. 1960, homon. posterior (non P. purpureum var. pubescens (A. Nels.) Harrington, 1954).

Petalostemon virgatum (rodlike, of the stems) Scheele, Linnaea 21: 461. 1848.- "Auf trocknen Prairieen bei Neubraunfels [Comal County, Texas]: Lindheimer."- Holotypus, formerly (?) B, not seen; presumed isotypi (cf. Wemple, 1970, p. 82, quoting Gray and A. Heller): Lindheimer 42, GH (3 sheets)! — Kuhnistera pulcherrima (fairest of all) A. Hell., Contrib. Herb. Franklin & Marshall Coll. 1: 50. 1895, a superfluous substitute. Petalostemon pulcherrimum A. Hell., Bull. Torrey Club 26: 593. 1899, a legitimate substitute (non P. virgatum Nees, 1840). Dalea helleri (Amos Arthur Heller, 1867-1944) Shinners, Field & Lab. 21: 165. 1953, a legitimate substitute (non D. pulcherrima S. & M. ex G. Don, 1832, nec D. virgata Lag., 1816).

This is the purple prairie clover most abundant and widespread over much of eastern Texas where, except in the valley of Red River and a few stations southward, it fills the role played by D. purpurea on the prairies of middle United States. Essentially Texan, it might be visualized as a magnified edition of the common mould, quite similar to D. purpurea in habit and foliage but with swollen heads and more flamboyant tassels of flower. The only strong differential characters between the two species are in the calyces, already mentioned above. My concept of var. pubescens is coextensive with Petalostemon pulcherrimum of Wemple’s revision (1970, p. 81), the difference in names being contingent on taxonomic judgement. Wemple discusses the synonymy in greater detail, supererogatory here. During independent preliminary study I formed the perhaps still arguable opinion that Petalostemon violaceum var. pubescens Gray, based on pubescent elements of D. purpurea and P. virgatum Scheele, was hopelessly ambiguous and reasonably discarded as a nomen confusum. Gray’s mixture, however, had been analyzed by Heller in 1901 and inferentially typified, with the result that the epithet pubescens can be preserved in the varietal category. My combination "D. compacta var. helleri", employed rather widely in herbarium annotation, is a nomen nudum.