Dalea nana var. carnescens

  • Title

    Dalea nana var. carnescens

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Dalea nana var. carnescens (Rydb.) Kearney & Peebles

  • Description

    151b.  Dalea nana Torrey var. carnescens (Rydberg) Kearney & Peebles

    (Plate CXXXVI)

    Variable in growth-habit, the stems commonly diffuse and incurved-ascending, then either monocephalous or branched distally, more rarely virgately ascending to erect, again branched or not; leaflets 5 in most leaves, sometimes 3 in the lowest and uppermost, exceptionally 7, varying from emarginate to short-acuminate, densely pilose or glabrescent above, the upper face often, but not always, turning verdigris- green when dry; spikes 1-1.3 (1.5) cm diam, the axis 0.5-4 (5) cm long; calyx-teeth (2.8) 3.4-4.2 (4.7) mm long; keel-blades 2.9-3.7 mm long; 2n = 14 (Mosquin).— Collections 72 (viii).

    Dry open hillsides and stony plains, mostly below 1200 m (4000 ft), widespread over most of Coahuila and the Edwards Plateau and Trans-Pecos n. of Rio Grande (Bravo), in Texas n. to San Saba, Taylor, Scurry, and Culberson counties, extending just into Eddy County, New Mexico, w. in scattered stations to centr. and s.-centr. Chihuahua, s.-e. Durango (at 1900 m); apparently somewhat isolated around the s.-e. edge of the Gila Basin in s.-e. Arizona (Santa Cruz and Cochise counties; to be expected in adjoining Sonora) and s.-w. New Mexico (Grant County); again disjunct on the low-lying limestones of lower Rio Grande valley in Webb and Zapata counties, Texas, and adjoining lowland Tamaulipas and Nuevo Leon, there climbing s.-ward into interior valleys (up to 1725 m) of Sierra Madre Oriental. — Flowering late March to September, perhaps throughout the year .—Representative: UNITED STATES. Arizona: Goodding 2276 (NY, UC); Darrow & Haskell 2278 (UC). New Mexico: Ripley & Barneby 4200 (NY); Degener 5032 (NY). Texas: T. & L. Mosquin 5677 (NY); Tharp 43-639 (NY, OKLA, UC); Moore & Steyermark 3237 (NY, UC); Tolstead 7132 (NY, UC); Barneby 13,533 (CAS, NY), 13,535 (NY), 14484 (CAS, DAO, NY); Correll & Schweinfurth 15,712 (RENNER). MEXICO. Tamaulipas: Ripley & Barneby 13,246 (NY). Nuevo Leon: Palmer 218 (F, NY, US); Ripley & Barneby 13,250 (MEXU, NY); V. L. Chase 7656 (F). Coahuila: Pringle 9015 (F, L, NY, Z); Palmer 217 (F, NY, US); Mueller 3116 (F); Stewart 475 (GH). Chihuahua: Stewart & Johnston 2037 (GH), 2062 (GH, TEX); Pringle 196 (BR, NY); Mosquin et al 6564 (NY); Ripley & Barneby 13,909 (CAS, NY). Durango: Ripley & Barneby 14,162 (NY).

    Dalea nana Torr. var. carnescens (Rydb.) Kearn. & Peeb., Jour. Wash. Acad. Sci. 29: 483. 1939, based on Parosela carnescens (turning flesh-pink, of the dried petals) Rydb., Fl. Rocky Mts. 483, 1063. 1917, as to descr., exclus. ref.— "Tex.—Colo. —Ariz."—No typus indicated in the protologue, and literature cited there all pertaining to var. nana. Rydberg, N. Amer. Fl. 24: 99. 1920, selected as neotypus Pringle 196, from Chihuahua, but this far out of given range. Lectotypus, annotated in Rydberg’s hand Parosela carnescens: Santa Rita del Cobre, Bigelow, in Mex. Bound. Surv., nov 5, 1851, NY!— Dalea carnescens (Rydb.) Bullock, Kew Bull 1939: 195. 1939; Tidest. in Tidest. & Kitt., Fl. Ariz. & New Mex. 183. 1941.

    Dalea rubescens (turning red, of the dried petals) Wats., Proc. Amer. Acad. 17: 369. 1882. — "Western Texas; at the Limpia Pass [ n.-e. of Fort Davis], 124 Wright, and at Fort Davis, Dr. V. Havard, 1881." — Lectotypus: Wright 124, GH! isotypi, NY, OXF! paratypus (Havard 5), GH! — Parosela rubescens (Wats.) Vail, Trans. N. Y. Acad. Sci. 14: 34. 1894.

    Dalea nana "var. elatior (pedalis) etc..." Gray, Pl. Wright. 1: 46. 1852, described but not formally named; Parosela elatior Vail, Bull. Torrey Club 24: 15. 1897, nom. illegit. Dalea nana var. elatior Gray ex B. L. Turner, Leg. Tex. 157. 1959, without validating reference to earlier description.

    Parosela whitehouseae (Eula Whitehouse, 1892- ) Tharp & Barkl., An. Esc. Nac. Ci. Biol. 4: 285. 1946 & Amer. Midi. Nat. 37: 781, fig. 1. 1947. — "...Menard County, Texas, July 7, 1928, B. C. Tharp s. n....." —Holotypus, TEX!

    Parosela lesueuri (David Hardeman LeSueur, 1909-1942) Tharp & Barkl., An. Esc. Nac. Ci. Biol. 4: 286. 1946 & Amer. Midi. Nat. 37: 783, fig. 2. 1947. — "Stockton to Sheffield, Texas, June 3, 1940, B. C. Tharp s. n.....’’ — Holotypus TEX!

    The status of var. carnescens is still debatable. The erect phase of it is often mistaken for D. aurea, the prostrate one for genuine D. nana, and the three entities collectively form an almost uninterrupted sequence of variations. However there is a better-marked discontinuity in flower-size between D. aurea and the remainder than between the two varieties of D. nana accepted here. Turner (1959, p. 157, map 99) suggested the possibility that the erect forms of var. carnescens are hybrids involving D. aurea. In western Texas D. aurea and D. nana are sympatric and sometimes closely associated, and the opportunity for pollen-exchange exists. But the same situation arises also in many places in central Texas, without giving rise to intermediate types. Moreover var. carnescens in more or less diffuse aspects extends far south and west of the limits to D. aurea and over vast territories in northern Mexico from which we have records of neither genuine D. nana nor D. aurea. The variants in stature and pubescence that are referred here to var. carnescens are reasonably, I think, interpreted as minor intraspecific modifications, without recourse to hypothetical introgression.

    The main range of var. carnescens extends over the limestone country of west-central Texas and Coahuila, surrounded north, east and west by var. nana, which is generally calcifuge. Where it invades the territory of var. nana, as in the lower Rio Grande valley and in contiguous south corners of Arizona and New Mexico, the two forms remain, wherever I have seen them, segregated by soil-preference, var. carnescens always on limestone rubble, caliche, or gypsum, and var. nana on acidic or neutral sands. It is possible that they should be recognized as distinct species, but (as mentioned above) occasional morphological intermediates occur, difficult to assign to variety (but none, as yet, accompanied by habitat data).

    My definition of var. carnescens coincides essentially with D. nana var. elatior of Turner (1959), wide enough to embrace those plants with erect monocephalous stems (Dalea rubescens Wats.) which simulate depauperate D. aurea as well as those diffusely branching ones referred by Rydberg’s key (1920, p. 70), depending on density of vesture, either to P. carnescens or P. nana. Rydberg misinterpreted the leaves of D. rubescens, the isotype of which at NY has lost its main cauline ones, as trifoliolate, and compared the species with D. jamesii, only remotely related. At the same time he was annotating as P. rubescens 5-foliolate specimens properly belonging there. The protologue of P. carnescens includes references to the plant of southeastern Colorado which had been listed in prior floristic works as D. nana "var. elatior" or D. rubescens, but this is genuine var. nana, not the plant that Rydberg actually described. Early collections of var. carnescens from Arizona had already been equated by Watson (Proc. Amer. Acad. 20: 360) with his own, thitherto Texan, D. rubescens. The more modern P. lesueuri and P. whitehouseae represent merely vigorous and starveling individual populations of the common form, the more vigorous, as often, greener.

    The varietal epithet elatior, often applied to var. carnescens in broader or narrower sense, is based on a misconception and has no nomenclatural standing in this context. As noted by Heller (Muhlenbergia 1: 30. 1901), the word elatior was used by Gray in Plantae Wrightianae merely as a descriptive term, the first of a phrase denoting difference from D. nana as then known. As employed by Porter & Coulter (Syn. Fl. Colo. 22) the name "var. elatior" is appended to a description of D. nana var. nana, and if validly published thereby, must fall into synonymy of var. nana. As employed by Turner, in the sense of the present var. carnescens, it fails by lack of reference to prior description to qualify as legitimate. The Parosela elatior of Vail, based ultimately on the same source, is illegitimate for other reasons.