Dalea pinnata

Rupert C. Barneby

52. Dalea pinnata (J. F. Gmelin) Barneby

(Plate LXI)

Perennial herbs sometimes of short duration often flowering the first season, with shallow, reddish taproot, (3) 4.5-9 (1) dm tall, glabrous to the inflorescence, the (1) 3-several finely striate, purple-castaneous, at least distally tuberculate stems at very base decumbent but thence abruptly erect, by anthesis naked toward base but upwardly continuously leafy to the sessile spikes, each primary cauline leaf subtending a spur, some of these near or well above middle produced into a spike, the whole inflorescence openly to quite densely corymbose, 4-15 (20) cm across the flat or low- pyramidal top, the thick-textured but often very narrow foliage green, the leaflets smooth above, punctate beneath; leaf-spurs 0.5-1.2 mm long; stipules narrowly subulate, subglandular, livid 0.4-1.5 (2) mm long, early dry and fragile; intrapetiolular glands minute or 0; post-petiolular glands present, often small, if prominent obtuse; leaves short-petioled, the primary cauline ones (drought-deciduous) 1-2.5 cm long, with punctate rachis and 3-13 well-spaced leaflets variable in outline from linear- involute to oblanceolate and flat or loosely folded, the longest 5-11 mm long, 0.3-2 mm wide, the terminal leaflet short-stalked, similar to the last pair, the leaves of axillary spurs shorter, mostly 3-foliolate, the leaflets smaller; spikes subcapitate, few- flowered, involucrate by 3-4 whorls of enlarged bracteiform stipular spurs, the outermost small and tipped by reduced or vestigial, 3-5-foliolate leaf-blades, the larger inner ones broadly ovate, at apex either acute or bidentate, up to 4-5.5 mm long, 3.5-4 mm wide, the whole involucre at anthesis 6-14 mm diam, passing upward into genuine bracts of abruptly narrower type, oblanceolate or elliptic, obtuse, ± enveloping the flowers, the involucral bracts persistent, papery, purple-castaneous, glabrous dorsally, ciliolate, the outermost often minutely gland-sprinkled; calyx (4) 4.5-7.8 (8.2) mm long, pilose with rather stiff ascending, finally divergent hairs up to 0.8-1.4 mm long, the subsymmetric tube a trifle constricted at mouth and a little recessed behind banner, (1.5) 1.7-2.3 (2.7) mm long, the ribs slender, castaneous, the intervals narrow, hyaline glandless, the teeth at first erect, divergent in fruit, narrowly linear becoming stiff and subsetiform, (2.5) 2.7-5.4 (6.2) mm long, all of ± equal length, densely plumose; petals white, glandless; banner (5) 5.4-8.6 mm long, the lanceolate or oblong-elliptic, basally cuneate or rarely subhastate blade ± as long as the linear claw; epistemonous petals resembling the banner but very shortly clawed, 3.7-6.8 mm long, the lanceolate or lance-oblong, rarely elliptic, acute, obtuse, or exceptionally emarginate blades 3-5 mm long, 0.8-1.4 mm wide; androecium 8.8-10.8 mm long, the column (4) 4.3-5.8 mm, the free filaments up to 4.2-5.5 mm long, the connective gland-tipped, the anthers 0.65-0.9 mm long; pod in profile half- obovate, 2.5-3 mm long, slightly convex ventrally, the prow only a trifle thickened, the style-base excentrically terminal, the valves hyaline and glabrous in lower half, thence thinly papery, pilosulous; seed ±1.7 mm long.

My comprehensive concept of D. pinnata is coextensive with genus Kuhnistera as understood by Rydberg (1920, pp. 135-6) and with Petalostemon subgen. Kuhnistera of Wemple’s revision. Rydberg recognized two species, K. pinnata and K. adenopoda; Wemple the same pair, but the first sundered into two geographic races. I follow Wemple precisely in the circumscription of three entities, disagreeing only (apart from the generic question discussed above) in my disposition of K. adenopoda as a third variety of D. pinnata coordinate with var. pinnata and var. trifoliata. See further below, under var. adenopoda.

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.

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