Dalea revoluta S.Watson
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Authors
Rupert C. Barneby
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Authority
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.
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Family
Fabaceae
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Scientific Name
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Type
"Guadalajara, among bushes; September. (496)." — Holotypus, collected in 1886 by Edward Palmer, GH! isotypi, NY, US!—Parosela revoluta (Wats.) Rose, Contrib. U. S. Nat. Herb. 10: 105. 1906. Thornbera revoluta (Wats.) Rydb., N. Amer. Fl. 24: 119. 1920.
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Synonyms
Parosela revoluta (S.Watson) Rose, Thornbera revoluta (Watts) Rydb.
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Description
Species Description - Herbaceous, perennial sometimes flowering the first season, (2.5) 3-7 dm tall, glabrous to the spikes, the diffuse or assurgent, green or purplish, angular-ribbed, copiously punctate or micro-tuberculate stems openly branched above the middle, the spikes terminal to all the branches, the foliage sparse, green, the leaflets punctate beneath; leaf-spurs 0.5-1.3 mm long; stipules narrowly subulate-aristiform, brown or purplish, 0.8-2.4 mm long; intrapetiolular glands impressed, sometimes minute; post- petiolular glands small, impressed or barely prominent; leaves 1.5-3 (3.5) cm long, shortly petioled, with narrowly margined rachis and (2) 3-9 pairs of linear to linear- elliptic, gland-mucronulate but either acute or emarginate, usually closely involute leaflets 2-8 mm long; peduncles 1-10 cm long; spikes dense, narrowly oblong-cylindroid, without petals 6-9 cm diam, the pilosulous axis becoming 1-3.5 cm long; bracts persistent, ovate-acuminate, -caudate, or rarely lance-acuminate, 1.5-4.5 mm long, the lowest glabrous dorsally, the rest pilosulous up to the middle or throughout, the distal half livid, gland-tuberculate, ciliate or ciliolate; calyx 2.9-4.2 (4.7) mm long, pilosulous with hairs up to 0.2-0.8 (1) mm long, the tube 1.6-2.1 mm long, its orifice subsymmetrical, the subfiliform ribs brownish-purple or pallid, not very prominent, the intervals membranous, eglandular, the triangular-acuminate or shortly aristate, entire teeth 1-2.4 (2.8) mm long, half as long up to 0.9 mm longer than the tube; petals white, eglandular, the banner rubescent, the epistemonous ones perched at or slightly below half-way betwen hyapnthium and anthers but at or close under separation of the filaments, all free; banner 3.8-5.1 mm long, the claw 1.8-2.9 mm, the ovate-cordate to deltate blade 2-2.3 mm long, 1.8-2.7 mm wide; wing and keel-petals similar, but the latter often a little shorter, proportionately broader, and more oblique at the incipiently auriculate base, the claw 0.2-0.5 mm, the oblanceolate to obovate blades 2.1-3.3 mm long, 1-1.5 mm wide; androecium (7) 9-10-merous, 6-7.5 mm long, the column 2.5-3.5 mm, the tassel 3.2-4 mm long, the connective gland-tipped, the yellow anthers ± 0.6 mm long; pod apparently as in D. grayi, not seen ripe. —Collections: 18 (4).
Distribution and Ecology - About thickets, along roads, and in open grassland, mostly 450-1350 m (1500-4500 ft), s.-ward ascending into the oak-belt and up to 2200 m (7300 ft), apparently local but locally plentiful along the w. slope and piedmont of Sierra Madre Occidental from s. Sonora and adjoining Chihuahua, especially on Rio Mayo, s. through Sinaloa to the valley of Rio Piaxtla (lat. 24° N); apparently disjunct in the canyons of Rios Santiago and Bolanos in n.-w. Jalisco but to be sought and expected in s. Sinaloa and Nayarit. — Flowering September to March.
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Discussion
13. Dalea revoluta Watson
(Plate XXXVII)
The specific epithet revoluta was poorly chosen for this rather weedy and inconspicuous dalea, the leaflets being involute, as common in the genus, but never revolute. It is closely related to D. grayi, which it resembles in the white petals and in the form of the flower- spikes, but differs in having commonly fewer and proportionately narrower leaflets, filiform or nearly so, spreading from the rachis and often gently incurved. Over the greater part of its known range D. revoluta is reasonably distinct, but on the Chihuahua-Sonora border, at the west edge of the range of D. grayi, there are puzzling populations, suggesting that these two species may not be genuinely discrete entities. Gentry’s plant from La Mesa Colorada (s. n., 1933, ARIZ), and others from Sierra Surutato, Sinaloa (Breedlove, NY) with up to 14 pairs of leaflets but a calyx lacking glands in the intervals of the calyx, are ambiguous. In the same general area D. revoluta and D. pringlei are sympatric, but the varieties of the latter present in the Rio Mayo drainage and vicinity either have purple petals or tall, erectly virgate stems a meter long or more, or in the rare event of the petals being white are more readily distinguished by very numerous (14-26 pairs) leaflets in main cauline leaves.
Southward from this critical area, where field-studies are required to solve unanswerable problems posed by the material now available, the documented range of D. revoluta is discontinuous and there is some evidence of geographic differentiation. In Jalisco the calyx-teeth are short, ± 1-1.5 mm long, and the bracts have dorsally naked tips. In Sonora and Sinaloa the teeth tend to be longer (mostly 2-2.5 mm) and the whole flower-spike tends to be more densely pubescent with longer hairs, the vesture commonly extending out to the tip of the interfloral bracts. A short-toothed but long-pilosulous calyx is found in one collection from Sinaloa, however, and the variation may well turn out, as the gaps in the range are filled in, to be clinal in nature and much less abrupt than now appears.
In southern Sonora Gentry found D. revoluta in good repute as a source of honey; it is known there as Popote chiquita, so distinguished from the true Popote which is D. pringlei.
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Objects
Representative: Sonora: C. E. Lloyd 383 (GH, NY, UC); Gentry 771 (ARIZ), 1104 (F, GH), 1428 (ARIZ, MEXU, UC); Gentry, Barclay & Arguelles 19,311 (US), 19,396 (US). Sinaloa: Gentry 5187 (ARIZ, MEXU); Ortega 460 (MEXU), 723 (ENCB, F). Jalisco: Rzedowski 17,683 (ENCB, TEX, MEXU); Pringle 2493 (BR, F, M, MEXU, NY, SD, W, Z), 11,425 (ARIZ, F, L, MEXU); Ripley & Barneby 14,058 (CAS, NY, US).
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Distribution
Sonora Mexico North America| Sinaloa Mexico North America| Jalisco Mexico North America| Chihuahua Mexico North America| Mexico North America|