Dalea elata

Title

Dalea elata

Author(s)

Rupert C. Barneby

Scientific Name

Dalea elata Hook. & Arn.

Description

17. Dalea elata Hooker & Arnott

(Plate XLI)

Potentially perennial becoming suffruticose, sometimes flowering precociously and then appearing annual, variable in stature and pubescence, commonly tall and erect, sometimes low, diffuse or decumbent, at anthesis (1) 2-22 (30) dm tall, the stems simple only when very short, usually branching near and above the middle, prominently ribbed but not or only obscurely glandular, the whole plant villosulous with ascending, soft and weak hairs mostly less than 0.7 mm long or variably glabrescent below the always silky spikes but rarely truly glabrous, the foliage green or greenish, the leaflets subconcolorous or much paler beneath, gland-dotted dorsally; leaf- spurs 0.5-1.4 mm long; stipules linear-subulate to setiform, 1.5-3.5 (4) mm long, usually orange-brown or livid distally, becoming dry and fragile; intrapetiolular glands very small and impressed or obsolete; post-petiolular glands small, often impressed; leaves (1) 1.5-5.5 (6.5) cm long, shortly petioled or subsessile, in juvenile plants all relatively short and with only 4-7 pairs of leaflets, but in taller, mature ones dimorphic, the main cauline with narrowly margined rachis and 6-12 pairs of elliptic, oblong-elliptic and mucronulate, to broadly oblong-obovate and obtuse, mostly flat, always thin-textured leaflets 2-12 mm long, the terminal one shortly stalked beyond and larger than the last pair, the leaves on the branchlets shorter, simpler, resembling those on the main stems of juvenile plants; peduncles at first leaf-opposed, then terminal to all the branchlets, 0.5-5 (6) cm long; spikes moderately dense, oblong-ovoid becoming cylindric or the shorter ones permanently ovoid, without androecia 8-10 mm diam, the villosulous axis becoming (1) 1.5-5.5 (7) cm long; bracts persistent at least through anthesis, commonly until fall of the calyx and pod, rhombic-lanceolate to narrowly elliptic, attenuate distally or at both ends, the blades greenish, brown, or livid-castaneous, prominently gland-charged, narrowly pallid-margined at base, plumose-ciliate, glabrous within, either villosulous or glabrescent dorsally; calyx 3.6-4.4 mm long, pilose at least at very base, always on the teeth, with fine ascending spiral hairs, the sometimes thinly pubescent or largely glabrate and lustrous tube 1.72 mm long, becoming strongly pleated, the prominent, thickened ribs usually yellowish, the recessed intervals narrow, membranous, charged with one vertical row of ±2-4, sometimes irregularly confluent, black or orange (rarely pallid) blister-glands, the orifice subsymmetrical, the triangular-aristate teeth 1.9-2.5 mm long, as long or longer than the tube; petals whitish, drying ochroleucous, eglandular or the banner charged at apex with a minute grain, the early caducous inner petals elevated 1.8-2.8 mm beyond the hypanthium rim, the keel-parts separate even in the bud; banner 3.2 -4.9 mm long, the slender claw 2.1-3 mm long, the deltate-cordate or reniform blade erect, open at base, 1-2.2 mm long, 1.6-2.6 mm wide; wing- and keel-petals similar in form, the latter a trifle more obviously oblique but scarcely broader, 1.8-2.4 mm long, the claw 0.2-0.4 mm long, the oblong-elliptic to -obovate, obtuse blade 1.6-2 mm long, 0.7-0.9 mm wide; androecium (9) 10-merous, 4.4-6 mm long, the longest filament free for 1.6-2 mm, the pale yellow, gland-tipped anthers ± 0.4 mm long; pod obliquely obovoid or triangular-obovate in profile, disregarding the terminal but excentric style-base ± 2 mm long, crested ventrally in the upper half, densely barbate across the top, the valves membranous and glabrous in the lower 1/2 or 2/3, thinly papery but opaque and often charged with several minute glands distally; seed ± 1.3—1.6 mm long. — Collections: 30 (i).

Brushy and grassy hillsides and banks of ravines, sometimes along highways, commonly associated with arid tropical thorn-scrub but ascending into the lower edge of the oak-belt, 20-1550 m (± 70-5170 ft) but mostly below 1000 m, widely dispersed along the Pacific slope of Mexico from southern Sonora to western Jalisco, thence east up the valley of Rio Grande to Guadalajara; also in scattered stations in the Balsas Depression and Sierra Madre del Sur in Estado de Mexico, Morelos, and Guerrero; and somewhat isolated on the north slope of the Coast Range in western Chiapas (to be expected in Oaxaca) and on the Atlantic slope in Veracruz.— Flowering in the dry season, mostly from November onward, but sometimes (especially northward) in spring and summer. —Representative: Sonora: Gentry 3613 (ARIZ, F, UC), 4858 (NY, UC). Sinaloa: Gentry 5678 (ARIZ, NY, MEXU), 5696 (ARIZ), 5803 (ARIZ). Durango: Palmer 164 (F, GH, NY, UC); Gentry 5242 (ARIZ, GH, MEXU, NY). Nayarit: Rose et al. 14,204 (GH, NY, US). Jalisco: Mexia 1831 (F, GH, UC). Mexico: Hinton 3338 (F, MEXU, NY, US), 15,780 (F, NY, UC). Morelos: Pringle 10,402 (ARIZ, F, L, UC). Puebla: Froderstrom & Hulten 1037 (F. NY). Guerrero: Hinton 15.420 (GH, NY, UC, US). Veracruz: Purpus 5741 (F, NY, UC); M. Sousa 2989 (MEXU). Chiapas: Matuda 1969 (ARIZ, F, MEXU).

Dalea elata (tall) H. & A., Bot. Beechey Voy. 416. 1840. — "Hab. Acapulco."— Holotypus, collected by Lay and Collie in 1840, K! isotypus (fragm.), NY! — Parosela elata (H. & A.) Rydb., N. Amer. Fl. 24: 79. 1920.

Dalea flava (yellow, the flowers so fading) M. & G., Bull. Acad. Brux. 10²: 40. 1843. —"...dans les ravins humides de Zacuapan et de Mirador, a 3000 pieds..." — Holotypus, Galeotti 3405, from "Barranca de Zacuapan", Veracruz, collected in January, 1840, BR (herb. Martius.)! —Parosela flava (M. & G.) Rydb., N. Amer. Fl. 24: 79. 1920.

Parosela pauciflora (few-flowered, inappropriate) Rose, Contrib. U. S. Nat. Herb. 10: 106. 1906. — "Type... collected by C. G. Pringle... near Guadalajara, Jalisco, December 12, 1888 (no. 1825)." — Holotypus not found at US; isotypi, K, M. MEXU, NY, UC, W, Z!

Due partly to great differences in stature between flowering and therefore apparently or truly mature plants derived from different populations, and partly to much variation in pubescence of the foliage and calyx, D. elata eludes neatly exact definition. In general aspect it combines something of the habit of D. carthagenensis with the spikes of D. leporina, at the same time lacking any marked individual character of its own. In fine detail the flower is like that of D. revoluta and D. grayi, with this difference: the filaments are separated for a shorter space and the inner petals, in consequence, appear to perch further from the point of separation. This small technical character sufficed to refer D. elata, in Rydberg’s classification, to Parosela, remote from its close relatives which were transferred to Thornbera.

My inclusive concept of D. elata is exactly coextensive with Parosela XIV. Flavae Rydb., which was composed of a common, more or less densely pubescent P. flava and a glabrate P. elata. In the typus of D. elata the stems are almost hairless, the leaflets are glabrous on both sides and glaucescent beneath, while the calyx-tube and back of the bracts are also nearly glabrous. However a topotype from Acapulco (Palmer 494) shows remnants of villosulous vesture on the upper stem and leaf-rachis; in Haenke 1617 a glabrous calyx-tube and glabrous bracts are found on the same plant with thinly villosulous but bicolored leaflets; and in Hinton 3338 (NY) bicolored leaflets densely pubescent both sides are combined with the ordinary villous calyx. Since the habit of growth, the flower, and other features are identical, I feel confident that D. elata and D. flava are best interpreted as pubescence-variants of one species.

More striking than the differences in vesture, so commonplace in Dalea, is the variation in stature and, correlated with stature, in number of leaflets, in plants of D. elata collected in full flower and fruit. Southward from Sinaloa and Durango the mature plant is obviously perennial, with one to several, erect or assurgent, eventually indurated or truly suffrutescent stems that deserve the epithet elata by reachins heights of one to two, more really three meters. In such plants the main cauline leaves, which are deciduous late in season, have seven or more, sometimes up to twelve pairs of leaflets; upward, on branch- lets of the panicle or on sterile lateral shoots, the leaves are reduced in size and the leaflets reduced to some four to six pairs. At low elevations in southern Sonora and in Sinaloa the plants often flower as diffuse herbs, sometimes during the first season’s growth, appearing annual in consequence. Such plants develop no long cauline leaves; all are about 4-5- foliolate but not otherwise different from leaves in the panicle of the taller forms. Several collections from the Rio Mayo valley collected by Gentry were segregated by Standley under an unpublished herbarium name, but I interpret them as representing a juvenile state of D. elata. At Alamos H. D. Ripley collected the same thing beginning to flower in February, and he reported that all individuals seen were of the same apparently annual type with weak, diffuse stems. It seems possible that the desert climate at the edge of the Sonoran Desert may have operated to select a rapidly flowering and rapidly maturing ecotype, and this may eventually require taxonomic status. For the present I must mention that typical, tall, obviously perennial D. elata was also collected by Gentry in the same region, albeit at greater elevations in the foothills.

I readily endorse Rydberg’s reduction of Parosela pauciflora. In describing it, Rose seems to have overlooked D. elata and D. flava entirely. The earliest known collection of D. elata was made by Haenke in 1791, very likely near Acapulco or along the camino real between Acapulco and Mexico City.