Dalea
Dalea albiflora
Rupert C. Barneby
9. Dalea albiflora Gray
(Plate XXXV)
Perennial from an eventually woody root and short caudex, (2) 2.5-5 (7) dm tall, silky-villosulous with weakly ascending (the stems sometimes with horizontal or sub- retrorse) hairs up to 0.3-1 mm long, the erect or less often diffuse stems usually branched near the base and also distally, sparsely glandular-verruculose, the foliage greenish or cinereous, the leaflets punctate beneath; leaf-spurs 0.4-0.9 mm long, charged on each side with a gland; stipules linear-subulate to subaristiform, 1-4.5 mm long, usually livid and glabrescent; intrapetiolular glands minute or obsolete; post- petiolular glands prominent, conic, orange or purplish; leaves 1-4 cm long, sessile or shortly petioled, with margined, greenish or sparsely punctate rachis and (6) 8-17 (20) pairs of oblanceolate, oblong- or linear-elliptic, more rarely oblong to narrowly obovate, mostly emarginate or very obtuse, flat or folded leaflets (1.5) 2-7 (10) mm long; peduncles terminal to all branches, 0.5-8.5 cm long; spikes dense but not conelike, ovoid or narrowly conic in outline becoming oblong- or narrowly cylindroid, without petals or androecia 7-10 mm diam, the villosulous axis becoming (1) 1.5-6 (7) cm long; bracts persistent, narrowly triangular to triangular-acuminate, pubescent dorsally (the lowest sometimes glabrate), the tips usually livid-castaneous and ± glandular; calyx (2.8) 3.2-5.1 mm long, pilosulous externally, the tube (1.9) 2-3 (3.3) mm long, deeply cleft behind the banner, the slender ribs becoming prominent, yellowish or brownish, the intervals membranous and charged with one row of ± 3-6 yellow glands, the triangular-cuspidate teeth entire, (0.9) 1.1-1.8 (2.1) mm long; petals white, eglandular, the epistemonous ones perched close to or shortly below separation of the filaments; banner (4.4) 5-6.4 mm long, the claw (1.8) 2-3.3 mm, the oblong- ovate or -elliptic, basally cuneate or subcordate blade (2.6) 3-4 mm long, (2) 2.2-3.4 mm wide; wing- and keel-petals similar, (3.4) 3.8-5.8 mm long, the claws (0.6) 1-1.9 mm, the oblanceolate to oblong blades usually cuneate at base, (2.7) 3.1-4.4 mm long, (0.8) 1.3-1.9 (2.2) mm wide, those of the inner pair sometimes more broadly obovate-oblanceolate and minutely auriculate at base on the inner side; androecium 10-merous (but one anther sometimes barren), (5) 6-8 mm long, the filaments free for ± 3.5-4.5 mm, the connective gland-tipped, the yellow anthers 0.4-0.6 mm long; pod broadly obliquely obovoid, 2.2-2.8 mm long, 1.7-2.1 mm wide, the style-base terminal but excentric, the valves in distal third thinly papery, villosulous, and gland- sprinkled, glabrous and hyaline proximally; seed 1.6-2 mm long. — Collections: 75 (iii).
Dry stony hillsides and grassy flats in the oak and pine belts of the Sierra Madre, northward coming out onto valley grasslands, 1050-2250 m (3500-7300 ft), common and locally abundant from extreme n. Durango (mpo. Villa Ocampo) through w. Chihuahua and adjoining Sinaloa (Sa. Surutato) and Sonora to the headwaters of the Gila River in centr. and s.-e. Arizona (n. to Yavapai, Gila, and Graham counties) and s.-w. New Mexico (to Grant and adjoining Sierra counties). — Flowering primarily in September to November, sometimes again in spring. —Representative: UNITED STATES. Arizona: Blumer 1476 (L, NY, W); Kearney & Peebles 14,460 (NY, UC); Maguire 12,129 (NY, UC). New Mexico: Metcalfe 1405 (NY, UC); Barneby 5120 (CAS, NY). MEXICO. Sonora: Hartmann 134 (F, NY, UC); S. S. White 3489 (ARIZ, MICH). Chihuahua: Pringle 1586 (F, MICH, UC), 990 (F, NY); M. & G. Ownbey 2023 (F, NY, UC); Gentry 2861 (ARIZ, F); Pennell 18,787 (GH, NY); Ripley & Barneby 13,870 (CAS, NY, US); Goldman 159 (GH, NY). Durango: Pringle 13,515 (ARIZ, L, M, MICH, TEX). Sinaloa: Breedlove & Thorne 18,559 (NY).
Dalea albiflora (white-flowered) Gray, Pl. Wright. 2: 38. 1853. — "Hill-sides on the San Pedro and Barbocomori, Sonora; Sept. (987)." — Holotypus, collected in 1851 by Charles Wright, GH! isotypi, NY, US! — Parosela albiflora (Gray) Vail, Trans. N. Y. Acad. 14: 34. 1894. Thornbera albiflora (Gray) Rydb., Jour. N. Y. Bot. Gard. 20: 66. 1919.
Dalea ordiae ("Mrs. Dr. Ord", a friend of J. G. Lemmon) Gray, Proc. Amer. Acad. 17: 200. 1882. — "Plains near Bowie and Rucker Valley, S. Arizona, Lemmon, 1881— Holotypus, from "Camp Rucker, Chiricahua Mts., Mrs. Dr. Ord, Sept. 1880 (from J. G. Lemmon)", GH! — Parosela ordiae (Gray) Vail, Trans. N. Y. Acad. Sci. 14: 34. 1894; Heller, Catal. N. Amer. Pl., ed. 2, 6. 1900. Thornbera ordiae (Gray) Rydb., N. Amer. Fl. 24: 119. 1920.
Parosela watsoni (Sereno Watson, 1826-1892) Rose, Contrib. U. S. Nat. Herb. 10: 106. 1906.— "Type U. S. National herbarium no. 24472, collected by Dr. E. Palmer at Frayles, Chihuahua, 1885 (no. 252)..." — Holotypus, US! isotypi, GH, NY, UC! — Thornbera watsoni (Rose) Rydb., N. Amer. Fl. 24: 117. 1920. Dalea watsoni (Rose) Gentry, Rio Mayo Plants 140. 1942, excl. syn.
Thornbera villosa (softly pubescent) Rydb., N. Amer. FL 24: 118. 1920.— "Type collected in the Santa Rita Mountains, Arizona, 1902, Griffiths & Morris 130..." — Holotypus, NY! — Th. albiflora ssp. villosa (Rydb.) Wiggins, Contrib. Dudl. Herb. 3: 54. 1940. Dalea rydbergii (Per Axel Rydberg, 1860-1931) Tidest. in Tidest. & Kitt., FL Ariz. & New Mex. 183. 1941 [non D. villosa (Nutt.) Spreng., 1826].
Dalea albiflora var. brevibracteata (with short bracts) Jones, Contrib. W. Bot. 12: 7. 1908. — "Colonia Juarez, Chihuahua, Mex...also Guayanopa Canon and San Diego Canon, Sept. 1903..." — Lectoholotypus, from San Diego Canyon, 16 Sept 1903, Jones s. n., POM! paratypus, from Colonia Juarez, 12 Sept 1903, in bud only, Jones s. n., POM!
Thornbera leucantha (white-flowered) Rydb., N. Amer. FL 24: 118. 1920.— "Type collected near Providencia, Durango, Sept. 11-12, 1898, E. W. Nelson 4996.." — Holotypus, US! isotypus, NY!
Petalostemon pilulosus (with little balls, of the immature spikes) Rydb., N. Amer. FL 24: 128. 1920.— "Type collected in Arizona, 1891, Nealley 237.." — Holotypus, NY!
Dalea gentryi (Howard Scott Gentry, 1903- ) Standi., Field Mus., Bot. 22 (1): 26. 1940. — "Mexico: Arroyo Hondo, Sierra Charuco, Chihuahua, in canyon bottom among pines, September 12, 1935, Howard Scott Gentry 1809.— Holotypus, F! isotypi, ARIZ, GH, MEXU, NY, UC, US!
My concept of D. albiflora embraces five of Rydberg’s species of Thombera, one of Petalostemum, a variety of D. albiflora proposed by M. E. Jones, and the more recently described D. gentryi Standi. The weight of synonymy suggests an extraordinarily polymorphic species, but it is in reality variable in only a few, relatively trivial and, it appears, uncorrelated features, notably in the length and density of the pubescence, flower-size (and in consequence thickness of the spikes), and length of bracts and calyx-teeth relative to that of the calyx-tube. The commonest type of pubescence consists of sinuous, ascending hairs mostly less than 0.4 mm long, occasionally mixed on the stems with some longer hairs. In southeastern Arizona and northern Sonora the pubescence of the stem is often horizontally spreading or even slightly retrorse, the longer hairs varying from ±0.4 to nearly 1 mm long. To this type belong the original D. albiflora and Thornbera villosa. Gray described D. ordiae as related closely to D. albiflora but different in its shorter-toothed, more prominently glandular calyx combined with less densely pubescent foliage, but from the vantage point of after-knowledge, based on a now extensive herbarium record, these contrasts seem feeble and in practice are unworkable. Rydberg thought that Th. ordiae could be separated from Th. albiflora by its short bracts and relatively short leaflets, but these two characters are not necessarily associated, and the majority of specimens annotated as Th. albiflora (NY) by Rydberg have the short bracts attributed to Th. ordiae. Kearney & Peebles (1960, p. 435) divided the Arizona material into a relatively coarse, broad-leaved D. albiflora and a more slender, silky, narrow-leaved D. ordiae but this is an artificial sorting of specimens, the species so defined being confluent morphologically and sympatric in dispersal. A slender form of D. albiflora, with narrow spikes, was collected by Charles Wright as early as 1851, and mentioned by Gray in Plantae Wrightianae as an unnamed forma; similar plants served as basis of Dalea gentryi. In general it may be said that the populations in Arizona and New Mexico tend to have coarser, more erect stems and thicker spikes than the diffuse, smaller-flowered (and often smallleaved) populations in Chihuahua and Sonora, but the passage between the extremes is gradual and now well documented. The type-collection of Parosela watsoni is mostly in advanced fruit, has narrow spikes but long pubescence; it is one of the most clearly intermediate forms.
References: [Article] Barneby, Rupert C. 1977. Daleae Imagines, an illustrated revision of Errazurizia Philippi, Psorothamnus Rydberg, Marine Liebmann, and Dalea Lucanus emen. Barneby, including all species of Leguminosae tribe Amorpheae Borissova ever referred to Dalea. Mem. New York Bot. Gard. 27: 1-892.Multimedia:
