Dalea pinnata

  • Title

    Dalea pinnata

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Dalea pinnata (Walter ex J.F.Gmel.) Barneby

  • Description

    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.