Dalea lamprostachya
Rupert C. Barneby
128. Dalea lamprostachya Barneby
(Plate CXIII)
Probably shrubby but of unknown stature, glabrous to the inflorescence, with smooth, livid-castaneous young stems, the foliage dark green, the thick-textured leaflets smooth above, punctate dorsally and marginally with livid glands, the spikes thinly pilose; leaf-spurs 0.8-1.3 mm long; stipules lance-subulate, livid, 1.5-4 mm long; intrapetiolular glands 3, blunt; post-petiolular glands large, prominent, blunt; leaves shortly petioled, the main cauline ones ±2.5 cm long, with narrowly thick- margined, punctate rachis and 4-5 pairs of narrowly oblong-elliptic, obtuse, openly boat-shaped, gland-crenulate leaflets 6-11 mm long, the cauline leaves each subtending a spur clad in similar but smaller leaves; peduncles terminal to leafy branchlets, 1.5-5.5 cm long; spikes moderately dense, the many flowers subcontiguous when pressed but not fully concealing the thinly pilose axis, without petals obtusely ovoid becoming cylindroid ±18 mm diam, the axis finally 4-9 cm long; bracts persistent, dimorphic, the lowest broadly lanceolate from cuneate base, thick-textured and densely glandular from base upward, glabrous, 5-7 mm long, the interfloral ones oblanceolate, up to 9 mm long, acuminately narrowed downward from near middle, thick- textured distally, thinly long-pilose on back and margins; calyx (sessile) 8.7 mm long, thinly pilose with fine straight ascending and spreading spiral hairs up to 1.7-2.2 mm long, the tube (measured to dorsal sinus) 3.2 mm long, strongly recessed behind banner and the orifice hence oblique, the ribs prominent, orange-castaneous, the membranous intervals charged with 3-5 very small, irregularly 1-seriate, subtransparent glands, the teeth narrowly triangular-acuminate, livid-nigrescent, gland-spurred, of about equal length, stellately spreading and plumose in fruit, the dorsal one 5.5 mm long; petals bicolored, the banner opening white, then rubescent, the epistemonous ones rose-purple (the keel-blades pale-edged externally), perched low on androecium (1.5-2 mm above hypanthium), all glandless; banner 9 mm long, the claw 6 mm, the deltate-cordate, subacute, ± hooded blade recurved through 40°, 4 mm long, 5.2 mm wide, recessed down top of claw into a groove opening adaxially; wings 9.8 mm long, the claw 4.1 mm, the oblong-oblanceolate blade 6 mm long, 3 mm wide; keel 11.7 mm long, the claws 5.3 mm, the broadly obovate-elliptic blades 7 mm long, 4.5 mm wide; androecium 10-merous, 11 mm long, the longer filaments free for 3 mm, the connective gland-tipped, the anthers 0.85-1 mm long; pod in profile broadly obovate, the style-base lateral just below apex, 3.5 mm long, 3 mm wide, the valves glabrous, membranous at very base, thence firm, livid, rugulose; seed 2.2 mm long.— Collection: 1 (typus).
Habitat not recorded, but to be sought in the oak-pine belt near or above 1100 m, known only from Sierra de Chavarria, a spur of Sierra Madre Occidental projecting w. from the main chain across the Durango-Sinaloa boundary in lat. ± 23° 40 N; perhaps also (cf. discussion) on Cerro San Juan near Tepic, Nayarit. — Flowering probably in winter.
Dalea lamprostachya (with splendid spikes) Barneby, sp. nov., affinitatis ignotae, cum D. versicoloris varietatibus nonnullis ob calycis longidentati formam pubemque com- paranda, sed bracteis magnis persistentibus, floribus spicisque maximis, necnon ovario glaberrimo distinctissima. A D. sericocalyce (Rydb.) Riley verosimiliter sympatrica et quoad calycem longidentatum vexillique formam simili foliolis angustis carnosis glabris, bracteis persistentibus necnon ovario glabro distantior videtur. — Verosimiliter frutex, infra spicas glaberrima; folia majora caulina ± 2.5 cm longa, foliolis 4-5-jugis oblongo- ellipticis navicularibus crasse carnosis 6-11 mm longis, facie inferiori et secus marginem subcrenulatam glanduloso-punctatis; spicae brevipedunculatae maximae subdensae multiflorae 4-9 cm longae, petalis androeciisque ablatis ± 1.8 cm diam; bracteae persistentes dimorphae, imae glabrae ex ipso basi crasse herbaceae lividae, interflorales oblanceolatae infra medium submembranaceae margine dorsoque supra medium pilosae; calycis pilis rectis fere 2 mm longis pilosi tubus 3.2 mm longus post vexillum valde retroscissus, dentes triangulari-caudati inter se subaequilongi 5-5.5 mm longi; petala bicoloria, vexillo albido mox rubescenti, epistemoneis purpureis multo infra medium androecium insidentibus, carinae laminis 7 mm longis, 4.5 mm latis; ovarium ac legumen glabra, hujus valvulae supra basin membranaceum firmae lividae. — Sinaloa (or perhaps adjoining Durango): Sierra de Chavarria, anno 1921, Jesus G. Ortega 4053. — Holotypus, US; isotypus, MEXU.
A remarkable dalea, notable for the livid-castaneous color of the stems, the relatively few (9-11) but long leaflets of thick texture, and handsomely barbate fox-tail spikes of large white and purple flowers interleaved with persistent, glandular bracts. Because of the long-toothed calyx clad in long spiral hairs it is natural to compare D. lamprostachya with D. versicolor, a species diverse internally but in all its phases separable by its deciduous bracts, gland-tipped petals, and gland-sprinkled, more or less pilose ovary and pod. The form of D. versicolor that most nearly resembles D. lamprostachya in vegetative characters is var. involuta, but this differs further in its smaller flower and narrower spike. Sympatric varieties of D. versicolor have more numerous, smaller leaflets, or pubescent foliage, or both. A dalea perhaps more closely related, though not really similar, is the still poorly known D. sericocalyx, collected only once in the same segment of Sierra Madre Occidental, somewhere between Mazatlan and Durango. This resembles D. lamprostachya in its long-toothed calyx and form of petals, but differs greatly in its pubescent foliage, more numerous leaflets of broad outline, and deciduous bracts, The growth-form and stature of D. lamprostachya and D. sericocalyx are unknown, so that an evaluation of their possible kinship is not really possible.
Sterile specimens of a dalea probably referable to D. lamprostachya were collected at about 1100 m on the north slope of Cerro San Juan west of Tepic, Nayarit (Ripley & Barneby 14,049a, CAS, NY), showing no sign of flower-buds in early October although bearing the naked spike-axes of the preceding season. These plants, which occurred in small quantity and as isolated individuals in the understorey of open pine-forest, took the form of a tall virgately monopodial shrub, the castaneous stem simple for a meter or more and branched distally into a small leafy panicle. The foliage was notably lustrous when fresh, vivid green. The leaflets are remarkable for bearing a row of glands on or close to the more or less involute margins, which appear minutely undulate-denticulate when dry.
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:
