Dalea tenuifolia

  • Title

    Dalea tenuifolia

  • Author(s)

    Rupert C. Barneby

  • Scientific Name

    Dalea tenuifolia (A.Gray) Shinners

  • Description

    51.  Dalea tenuifolia (Gray) Shinners

    (Plate LX)

    Slender perennial herb from a brown woody root and knotty caudex, (1.5) 2-5 (5.5) dm tall, the leafless base of the usually decumbent or diffusely ascending stems always densely pilosulous, the plant thence either glabrous to the inflorescence, or the stem, leaf-rachis, or lower face of leaflets (or some of them) pilosulous with fine, forwardly subappressed to widely spreading hairs up to 0.3-0.8 (1.3) mm long, the pale green or stramineous, ribbed stem either simple or branched only above middle or rarely throughout, the sparse foliage green, the leaflets little bicolored, smooth above, punctate beneath; leaf-spurs 0-1 mm long; stipules narrowly linear-caudate or setiform, livid or castaneous, becoming dry and fragile; intrapetiolular glands minute; post-petiolular glands small but prominent, obtuse; leaves petioled, the primary cauline ones 2-4 cm long, with thick-margined rachis and 3-5 linear-oblanceolate, either emarginate, obtuse, or subacute and gland-mucronulate, usually involute leaflets up to 1-2.2 cm long, the short-stalked terminal one a little longer than the rest, the leaves of axillary spurs shorter, with mostly 3 leaflets of same type but smaller; peduncles 1.5-8 cm long; spikes dense in bud, loosening during and after anthesis, becoming oblong-cylindroid or (the lesser lateral ones) subglobose, never conelike, the flowers (pressed) appearing 3-4-ranked, the whole without petals 8-10 mm diam, the densely pilosulous, pitted axis (0.5) 1-7 (9) cm long; bracts deciduous by full (or certainly by late) anthesis, 2.5-4.5 (5.5) mm long, the body broadly flabellate-obovate to broadly oblanceolate, 1.2-2.4 mm wide, greenish-glaucescent, pilosulous and inconspicuously gland-dotted dorsally, glabrous within, contracted into a subulate or subulate-attenuate livid tail 1-2 (3) mm long; calyx (3.1) 3.4-4.5 mm long, densely pilose with spreading-ascending hairs up to (0.7) 0.9-1.5 mm long, the subsymmetrically obovoid tube not recessed behind banner, (1.6) 1.9-2.4 mm long, bluntly 10-angled, the ribs prominulous but very slender, the almost flat intervals densely castaneous- flecked but glandless, the teeth of subequal length but different shapes, the 3 dorsal ones lanceolate, 1.5-2.1 mm long, the ventral pair ovate-lanceolate to ovate, the blades plane, herbaceous or castaneous; petals rose-purple, eglandular; banner 5.5-6.5 mm long, the claw 3.2-4 mm, the broadly cordate, apically hooded, obtuse or emarginate blade 2.3-3.1 mm long, 2.6-3 mm wide; epistemonous petals 4-4.8 nun long, the claw 1-1.5 mm, the oblong or ovate-oblong, basally truncate to broadly cuneate blade 2.7-3.4 mm long, 1.2-1.5 mm wide; androecium 6-8.3 mm long, the column tipped, the anthers 0.9-1.5 mm long, yellow; pod 2.8-3.5 mm long, in profile obliquely half-obovate, the ventral suture concavely the dorsal convexly arched, the style- base excentrically terminal, the prow slender but prominulous, the valves hyaline and glabrous in lower 1/3, thence papery, pilosulous, commonly gland-sprinkled; seed ± 2 mm long; 2n = 14 (Wemple, 1970, p. 12); n = 7 II (Mosquin).— Collections: 36 (iv).

    Stony hilltops, rocky bluffs, and gullied badlands, commonly associated with limestone caprock but sometimes on granites or sandstones, 810-1350 m (2700- 4500 ft) and perhaps slightly higher w.-ward, locally plentiful over the short-grass prairies and arid grasslands drained by the upper Canadian, Cimarron, and Pecos rivers in the Texas and Oklahoma panhandles, the n.-e. quarter of New Mexico, and adjoining Colorado and Kansas, extending s. in Texas to the sources of the Brazos in Lubbock and Garza counties, on the Pecos s. to Fort Sumner, thence w. just to the edge of the Rio Grande valley in Sandoval County, in Kansas n. interruptedly to the head of Smoky Hill River in Wallace County; cf. Wemple, 1970, map 12.—Flowering late May to August, in New Mexico sometimes again in fall. — Representative: Kansas: McGregor 17,307 (NY); Barneby 14,990 (CAS, IA, NY). Colorado: Stephens & Brooks 21,842 (NY). Oklahoma: Waterfall 3122, 3165 (NY). Texas: E. J. Palmer 12, 503 (NY, UC), 13,855 (WIS); Reverchon 3008 (NY); Wemple 253, 255 (NY). New Mexico: Eggleston 20,176 (NY); Goodding 5654 (NY); T. & L. Mosquin 5729 (NY).

    Dalea tenuifolia (Gray) Shinners, Field & Lab. 17: 84. 1949, based on Petalostemon tenuifolius (thin-leaved) Gray, Proc. Amer. Acad. 11: 73. 1876. — "Arkansas, at the crossing of Red River, Dr. Newberry; New Mexico, Mr. Dieffendorfer (ex T. C. Porter), J. T. Rothrock." — Lectotypus, Rothrock 81 in 1874, collected probably at Algodones, s.-e. Sandoval County, New Mexico, GH (mounted with the conspecific paratypi mentioned above); isotypi, K, NY (herb. Canby), US (Rothrock 81)\ — Kuhniastera tenuifolia (Gray) O. Kze., Rev. Gen. 192. 1891.

    Petalostemon porterianus (Thomas Conrad Porter, 1822-1901) Small, Fl. S. E. U. S. 1332. 1903. — "Type, Leavenworth, Ark. to El Paso, Tex., Dieffenderfer, in herb. Lafayette Coll." — Holotypus presumably burned with T. C. Porter’s herbarium; isotypus, labelled by Porter = paratypus of P. tenuifolius listed in preceding paragraph; clastotypus (fragm. retained by Small), NY! isotypus, GH!

    Petalostemon rothrockii (Joseph Trimble Rothrock, 1838-1922) Rydberg, N. Amer. Fl. 24: 134. 1920.— "Type collected in Arizona, 1874, Rothrock (Wheeler Exp., in herb. Columbia Univ.)." —Holotypus, presumably part of Rothrock 81, NY! = paratypus of D. tenuifolius.

    In the context of related prairie-clovers with few leaflets and purple flowers the characteristic features of D. tenuifolia, as pointed out by Wemple (1970, p. 77, fig. 11A), are the basally pilose stems and elongating spikes. The broad, thin-textured interfloral bracts are also distinctive. On the Staked Plains the species is sympatric with forms of D. purpurea, but in that region is found mostly on limestone caprock whereas D. purpurea is in the prairie sod or sands. On the Pecos-Rio Grande divide, however, D. tenuifolia forsakes the limestones and appears equally vigorous and at home on granitic bedrock and on gullied badlands.

    Wemple (1970) analysed the type-sheet in Gray Herbarium which bears all three collections cited in the protologue, but did not select a lectotype. I here choose Rothrock 81, which is represented by duplicates in several other herbaria, one of them being holo- type of P. rothrockii. Wemple overlooked the real place of publication of the last named, in the appendix to Small’s Flora, where the typus is cited in exact detail (cf. supra); the Dieffenderfer specimen at Gray can be no more than an isotype. If a neotype were needed, the fragment of Porter’s own specimen, retained by Small at NY, would be preferable. The origin of Rothrock 81 deserves a note. Rothrock himself cited under this number and figured in Wheeler's Report 98, PI. II. 1878 only one purple-flowered Petalostemon, using moreover Gray’s recently published name P. tenuifolius. Unquestionably these references are all based on one collection even though the data of locality differ, Gray giving "New Mexico", Rothrock "Arizona", the latter appearing on the label of the specimen in NY which became type of P. rothrockii. Rothrock’s collection of 1874 was serially numbered and his Nos. 77 (Asclepias verticillata), 78 (A. involucrata), 79 (Penstemon ambiguus) and 82 (Riddellia tagetes) were all cited from Algodones, a village on the Rio Grande near the north end of the Sandia Mountains in southeastern Sandoval County. Under No. 82 the place is mis-spelled Alcadones, and it seems likely that "Arizona" of the Report, later copied onto the label at New York, is another printer’s error. I myself have seen D. tenuifolia at Placitas a few miles east of Algodones, and I have no doubt that the latter is in effect the type-locality. Newberry’s crossing of Red River cannot, of course, have been in the present state of Arkansas but far upstream, very likely in the Texas Panhandle.