Dalea dipsacea

Rupert C. Barneby

19.  Dalea dipsacea Barneby

(Plate XLIII)

Erect annuals (1) 1.5-5.5 dm tall, glabrous to the inflorescence (the leaf-rachis and top of peduncle sometimes minutely puberulent), the stiff but slender, angular- ribbed, green, remotely micro-glandular stems either simple and monocephalous or branched above the middle and each branch monocephalous, the foliage ± bicolored, green above, paler and gland-dotted beneath; leaf-spurs up to 1 mm long; stipules setiform, pallid or brownish, 1-2.5 (3) mm long; post-petiolular glands small, pallid, scarcely prominent; intrapetiolular glands 2, minute; main cauline leaves (deciduous upward toward anthesis) 2.5-4 cm long, sessile, with broadly margined, ventrally flattened rachis and (5) 6-10 (12) pairs of oblong-oblanceolate, obtuse but gland- mucronulate, distally gland-crenulate, flat or loosely folded leaflets 4-8 mm long, the terminal one a trifle longer than the last pair, solitary; peduncles (0.3) 1.5-7 cm long; spikes very densely many-flowered, conelike, oblong becoming cylindric, including the bract-tails 1-1.2 cm diam, the thinly pilosulous axis concealed by flowers, becoming 1-4 cm long; bracts persistent, 5-6 mm long, glabrous except for the sometimes minutely ciliolate margins, the obovate body 2-2.5 mm long, embracing the calyx, hyaline in lower half, distally firm, green, and charged with a few small pale blister-glands, abruptly contracted into a firm, linear-acuminate, spreading and then incurved-ascending tail 2.8-3.8 mm long, the whole sharply keeled by a corneous midrib; calyx 1.8-2.3 (2.5) mm long, thinly pilosulous externally with fine, loosely ascending hairs up to 0.35-0.5 mm long, the membranous, pallid tube 1.1-1.5 mm long, a little recessed behind the banner, the ribs filiform, almost colorless, the broadly del- tate-ovate, terminally cuspidate, green or green-edged teeth 0.5-0.8 (1.1) mm long; petals eglandular, bicolored, the banner white, the inner pairs blue-violet, the epistemonous ones inserted at the separation of the filaments, the keel-petals free from the first; banner 2.4-2.9 mm long, the claw 1.1-1.5 mm, the erect, ovate, obtuse, loosely folded blade ±1.4 mm long, 1-1.2 mm wide; wings and keel-petals similar, the latter a trifle larger, 0.8-1.4 mm long, the subsymmetrically obovate, obtuse, 1-3- nerved blades 0.7-1.1 mm long, 0.4-0.7 mm wide, contracted at base into a claw 0.1-0.3 mm long; androecium (4) 5-7 (8)-merous, commonly with only 4-6 fully developed stamens, the whole 3-3.5 mm long, the filaments free and purple for up to 0.7-1.1 mm, the connective minutely gland-tipped, the anthers 0.3-0.35 mm long; ovary thinly pilosulous, the pod and seed unknown. — Collections: 2 (ii).

Grassy openings in oak or oak-pine forest, 900-1100 m (± 3000-3700 ft), forming colonies but apparently local, known only from two stations in the w. half of the Transverse Volcanic Belt in Michoacan (near Uruapan) and Nayarit (near Jalisco).—Flowering October to December.

Dalea dipsacea (teasel-like, of the conspicuously bracteate spike) Barneby, sp. nov., D. cliffortianae Willd. similis et affinis, sed bracteis longe subspinoso-caudatis dorso glabris flosculos subdimidio minores suffulcrantibus, androecio breviori (3-3.5 nec 5.5-6.7 mm longo) 4-8 (saepissime 5-7)-mero, foliolisque magis numerosis (foliorum caulinorum majorum 5-12, saepe 6-10, nec 3-7, saepe 4-6-jugis) absimilis. — Michoacan. Uruapan: barranca of Rio Cupatitzio ± 14 mi below Uruapan, Oct 12, 1965, Ripley & Barneby 14,113. — Holotypus, NY; isotypi, CAS, MEXU, MIXH, US. —Nayarit. Compostela: 11 mi s. of Jalisco, Ripley & Barneby 14,045. — Paratypi, CAS, NY.

The relationship of D. dipsacea to D. cliffortiana is obvious and close. They are similar in habit and it seems likely that D. dipsacea has been passed over for its common, weedy relative; it may well have a much more extensive range in Nueva Galicia than is known at present. The immediately distinctive feature of D. dipsacea is the spike of spinosely tailed bracts which are incurved at tip and so suggest, on a small scale, the hooked bristles of the Fuller’s Teasel. The shorter androecium composed of fewer fertile stamens and the more numerous leaflets are additional differential features. In foliage D. dipsacea resembles the marginally sympatric D. obreniformis, but this is quickly recognized by its little obcordate bracts tipped with a minute tail recessed into the terminal sinus.

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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