Monographs Details: Dalea nobilis Barneby
Authors:Rupert C. Barneby
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.
Family:Fabaceae
Scientific Name:Dalea nobilis Barneby
Description:Species Description - Probably suffruticose, possibly shrubby, up to 1 m tall, finely pilosulous throughout with soft, spreading hairs up to 0.35-0.5 mm long, the stems prominently ribbed, eglandular or nearly so, the foliage greenish, the leaflets pubescent both sides, verruculose beneath; leaf-spurs less than 1 mm long; stipules narrowly subulate, 1.8-2 mm long, becoming dry, fragile, deciduous; intrapetiolular glands 0; post-petiolular glands small, hemispherical or subimmersed, pilosulous; main cauline leaves (lowest not seen) up to 12 cm long, shortly petioled, with broadly green-margined, ventrally grooved rachis and ± 22-27 pairs of broadly oblong to ovate, flat leaflets, the lowest on the rachis largest, up to 6-8 mm long, the rest diminishing upward but the odd one (shortly stalked) slightly longer than the last pair, the upper leaves reduced both in length and in number and size of leaflets; peduncles terminal to branches, ± 1 cm long but appearing longer due to suppression of the upper leaves, the last ± 3 nodes marked only by stipules and rudimentary, sessile spikes of imbricated bractlets; spikes many-flowered, moderately dense, the calyces when pressed subcontiguous but falling into ± 2 ranks and exposing the villosulous axis, this becoming up to 9 cm long; bracts deciduous before anthesis, ovate-caudate, up to 7.5 mm long, the body ovate, boat-shaped, ± 3 mm long and in profile 1.3 mm wide, livid except for pallidly membranous margins, lustrously pilose and gland-sprinkled dorsally, glabrous within; calyx at anthesis ± 6.3 mm long (a trifle accrescent thereafter), lustrously pilose with fine straight spreading spiral hairs up to 1.3 mm long, the broadly campanulate, subtumid tube 3.3 mm long, nearly as broad, scarcely recessed behind the banner, the slender ribs livid, prominulous, the membranous pallid intervals charged with many small scattered golden glands, the teeth deltate- to broadly triangular-acuminate, of nearly equal length, the dorsal one ± 3 mm long (slightly shorter than the tube), the ventral pair broadest, all gland-spurred and -tipped; petals all purple from the first, the banner charged with a few tiny glands near the eye, otherwise eglandular, the inner petals elevated only 0.3-0.7 mm above the hypanthium-rim; banner 7.7 mm long, the claw 4.3 mm, the cordate, hooded blade suberect, 3.5 mm long, nearly as wide, closed at base into a shallow cornet; wings 7.5 mm long, the claw 2.8 mm, the oblong blade 4.9 mm long, 2.1 mm wide; keel 7.8 mm long, the claws 3 mm, the blades 5.1 mm long, 3 mm wide, united along their outer edges; androecium ± 9.4 mm long, 10-merous, the longest filament free for it 2.7 mm, the anthers it 0.8 mm long, exserted from the keel at anthesis; style at full anthesis exserted ± 3 mm beyond the anthers; ovules 2; pod broadly obliquely obovoid, compressed, 3.5 mm long, in profile 2.7 mm wide, the style-base subterminal at the upper corner, the valves very thinly papery or at base submembranous, semi-transparent, pilosulous and gland-sprinkled above the middle, the slender prow livid; seed ± 2.2 mm long. — Collection: 1 (o).

Distribution and Ecology - Open oak-woodland, on rhylolitic substrate, it 2000 m, known only from the type- locality in the valley of Rio Juchipila, a northern tributary of Rio Grande de Santiago in the s. prong of Zacatecas. — Flowering January to February.

Latin Diagnosis - Dalea nobills (of noble mien) Barneby, sp. nov., D. polystachyae (S. & M.) Barneby manifeste affinis, sed caulibus foliisque undique pilosulis, spica elongata, necnon androecio elongato antheras ad anthesin ultra carinam proferenti statim separanda. — Zacatecas: ladera riolitica con vegetacion de bosque bajo de Quercus macrophylla, 2000 m, Cerro de Pinones, 4 km al W de Pueblo Viejo, mpo de Juchipila, Jan 25, 1964, Jerzy Rzedowski 18,261.

Discussion:

(Plate LXVI)

This remarkably handsome dalea resembles D. polystachya in its many (up to 25 pairs) broad, flat leaflets, in fine detail of the calyx, and in shape of the petals, but may be recognized instantly by the softly pilose stems and herbage, the massive spike of calyces, and the exserted anthers. Ordinarily D. polystachya is entirely glabrous below the flower spikes, but the caudex rarely gives rise, late in the season, to thinly pilosulous sterile shoots bearing short, comparatively simple leaves. If the same type of pubescence were to extend upward along the flowering stems and adult foliage, the plant would resemble D. nobilis closely, but nothing of the sort is known at present. Mention has been made under D. polystachya of what is believed to represent a large-flowered phase which was described by Rydberg as Parosela lagopina. The typus of the latter, not since exactly matched, resembles D. nobilis in the proportions of the spike; unfortunately the flower is unknown at anthesis, so that the proportions of calyx to petals and androecium and the position of the anthers cannot be compared with those of D. nobilis. The androecium of D. lagopina is very long (± 11 mm after fall of the petals), so that the anthers may very well be exserted as in the present species; but the plant is glabrous to the spikes, in practice therefore easily separable. The keel and wings of D. nobilis are inserted on a column less than 1 mm distant from the hypanthium-rim, much closer to the floor of the calyx than those of any known form of D. polystachya or of so-called P. lagopina.

Distribution:Zacatecas Mexico North America| Mexico North America|

Narratives:Dalea nobilis
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