Dalea lanata var. terminalis

  • Title

    Dalea lanata var. terminalis

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Dalea lanata var. terminalis (M.E.Jones) Barneby

  • Description

    53b. Dalea lanata Sprengel var. terminalis (Jones) Barneby

    (Plate LXII)

    Stems rarely glandless, although only with a few scattered glands and these often concealed by vesture; vesture on the average a little shorter than in var. lanata, the longest hairs up to 0.2-0.45 (0.55) mm long, sometimes very sparse or, very locally, quite lacking and the plant glabrous throughout; calyx-tube 1.8-2.5 mm long, the longest tooth (1.3) 1.5-2.3 mm long; petals a trifle smaller than those of var. lanata, the blades of the epistemonous ones 2-3.4 mm long, 1.5-2 mm wide; n = 7 (Spellenberg, 1973); 2n = 14 (Mosquin). — Collections: 56 (v).

    Dunes and drift-sand on open plains, 930-1860 m (3100-6200 ft), locally abundant, very common along the Rio Grande Valley from Sandoval County, New Mexico, downstream to the Big Bend in Trans-Pecos Texas, n.-w. in New Mexico across the Puerco-Colorado divide to the Four Corners country in s.-w. Colorado and adjoining Utah and Arizona, extending thence through the Little Colorado valley to its confluence with the Colorado in Coconino County, Arizona; Virgin valley in s.-w. Utah (Washington Co.) and adjacent Arizona (Beaverdam); from the Rio Grande extending s. into the great dunes of northern Chihuahua (50-60 km s. of El Paso-Juarez) and, perhaps isolated, to the e. margin of Bolson de Mapimi in w.-centr. Coahuila (Sierra del Rey, near 27° N). — Flowering July to October, rarely earlier and sporadically later .—Representative: UNITED STATES. Utah: Holmgren 3799 (NY, UC). Colorado: Brandegee 1090 (NY, UC). Arizona: Eastwood & Howell 6466 (CAS, UC); Beasley 890 (NY); Barneby 5037 (NY). New Mexico: Heller 15,797 (NY, UC); A. Nelson 11,724 (NY, UC); McClintock & Robbins 6445 (NY, UC); Barneby 13,841 (CAS, NY), 13,849 (DAO, NY). Texas: Hinckley 3513 (NY); Warnock 5758, 13,672 (RENNER). MEXICO. Chihuahua: Gentry 8203 (UC); Thurber 727 (F, NY). Coahuila: Purpus 4490 (F, UC).

    Dalea lanata Spreng. var. terminalis (Jones) Barneby, comb. nov., based on D. terminalis Jones, Contrib. West. Bot. 12: 8. 1908. — "Common at El Paso, Texas...also Albuquerque... Also at Billing." — Lectotypus, collected by Marcus E. Jones at El Paso, 10 Sept 1884, POM (2 sheets)! paratypi, as indicated, POM! — Parosela terminalis (Jones) A. Heller, Muhlenbergia 6: 96. 1910.

    Dalea glaberrima (quite hairless) Wats., Proc. Amer. Acad. 22: 470. 1887.— "On sandhills, 30 or 40 miles south of Paso del Norte, Chihuahua (C. G. Pringle, September, 1886)."—Holotypus, Pringle 720, GH! isotypus, US! Parosela glaberrima (Wats.) Rose, Contrib. U. S. Nat. Herb. 10: 103. 1906.

    Dalea arenaria (of sands) Jones, Contrib. West. Bot. 12: 8. 1908.— "...at Sapio and Sabinal, Chihuahua, Mex...Sept. 10 and 20, 1903." — Lectotypus, collected by Marcus E. Jones at "Sapio" [probably = Sapello], 10 Sept 1903, POM (2 sheets)! isotypus, US! paratypus, from Sabinal, 29 Sept 1903, POM!

    Parosela subvillosa (somewhat pubescent) Rydb. in N. Amer. Fl. 24: 93. 1920.— "Type collected on sand near Paso del Norte, Chihuahua, September 23, 1886, Pringle 720, in part (herb. Columbia Univ.)." — Holotypus, NY! isotypus, US! Dalea subvillosa (Rydb.) B. L. Turner, Field & Lab. 18: 46. 1950.

    In general habit and appearance the common, gray-leaved form of var. terminalis is indistinguishable from var. lanata, the differential characters in form and vesture of the calyx requiring close scrutiny. In practice little difficulty is anticipated, the ranges of the two varieties, where they most nearly approach each other, being separated both in New Mexico and in trans-Pecos Texas by the Pecos-Rio Grande divide. I have seen only one morphologically intermediate specimen, H. & D. Correll 30,629 (RENNER) from the Rio Grande canyon in Brewster County; this combines the deltate calyx-teeth of var. terminalis, to which I refer it, with a pubescent calyx-tube. In Mesilla Valley between Las Cruces and Ciudad Juarez, and on dunes associated with the bolsones of Lago Guzman and other interior basins of adjoining northern Chihuahua, there occurs with the ordinary gray- villosulous form a plant with glabrescent or even quite glabrous stems and foliage, the Parosela glaberrima of Rydberg’s revision. Although very striking because of its rich green leaves, P. glaberrima differs from typical var. terminalis only in the loss of pubescence. This form was collected in October, 1852, by George Thurber, at Los Medanos, the great area of dunes lying about 60 km south of Ciudad Juarez, but his specimens (no. 727, F, GH, NY) attracted no particular attention. It was found next in 1886, in the same area, by Pringle, and in 1908, at points shortly to the west and northwest, by M. E. Jones; their collections furnished the types of D. glaberrima Wats, and D. arenaria Jones, respectively. Watson misinterpreted Pringle’s plant as an erect shrub related to what is called in this revision D. bicolor; this, I suspect, explains Jones’s duplication. Several collectors have found the glabrous and pubescent phases growing together, Wooton at Mesilla, New Mexico (Nos. 35, glabrous, 41, villous, both NY, UC), Correll & I. M. Johnston near the type- locality of D. glaberrima (carefully distinguished as Nos. 20,322A, glabrous, 20,322-B, villous, both RENNER). The typus of P. subvillosa from near El Paso represents a more or less intermediate, thinly pubescent phase. During the early stages of my study I annotated several sheets of the truly glabrous state as a variety of D. lanata, but as I have seen more material I have come to regard it as ano her instance of a phenomenon encountered repeatedly in Amorpheae, an abrupt loss or an abrupt acquisition of pubescence unrelated to any other variable feature. While the glabrous (or glabrescent) phases of var. terminalis occur only in a small part of the latter’s range they have acquired no independent dispersal of their own; I therefore think them reasonably reduced to one taxon variable in this one respect.

    The pubescent form of var. terminalis was collected first by Charles Wright in 1848, on the Rio Grande "60 miles below El Paso", that is in the vicinity of Fort Hancock, Brewster County, Texas, and again, at a place not recorded, in 1851 (Nos. 128, 981, both NY). These collections were identified by Gray as D. lanata.