Dalea cuniculo-caudata
Rupert C. Barneby
119. Dalea cuniculo-caudata P. G. Wilson
(Plate CVII)
Herbaceous or in age weakly suffruticulose, perennial but sometimes flowering the first season, the slender, brittle, virgately erect or rarely trailing, stramineous or brownish, smooth or distally subtuberculate stems 7-15 dm long, simple up to or beyond the middle and thence branching into an open, sparsely leafy panicle of silky spikes, glabrous below the inflorescence, the foliage bright green, the leaflets a little paler and black-punctate beneath; leaf-spurs less than 1 mm long; stipules subulate, livid, 0.5-0.9 mm long; intrapetiolular glands minute, impressed; post-petiolular glands prominent but small; leaves (0.8) 1.2-3 cm long, subsessile, with rather broadly margined rachis and 6-12 (14) pairs of narrowly oblong-elliptic or -oblanceolate, retuse or emarginate, cymbiform, thick-textured leaflets 1.5-4.5 mm long; peduncles slender, 1.5-7.5 (9) cm long; spikes very dense, ovoid or subglobose, the largest becoming oblong-cylindroid, without petals 10-12 mm diam, the pilosulous axis becoming 1-2 (2.5) cm long; bracts deciduous, narrowly lance-acuminate or sublinear, 2.5-5 mm long, livid or livid-tipped, the outermost dorsally glabrescent but ciliolate, the rest densely pilosulous on the back, all densely silky-pilosulous within; calyx 5-5.8 mm long, densely pilose with lustrous hairs, the tube 2.2-2.5 mm long, the ribs slender, the intervals glandless or charged with small, irregularly seriate, pallid glands, the deltate-aristate teeth unequal, the dorsal one longest, 2.5-3.1 mm long, all minutely gland-spurred; petals bicolored, the banner white (sometimes blue-tipped) fading dull pink-purple, the inner petals bright blue (exceptionally purple), elevated ± 1-1.7 mm above the hypanthium rim, the keel-blades united by their margins, the banner and keel (and sometimes the wings) charged at apex with a large blister-gland; banner 4.2-5 mm long, the claw 2-2.8 mm, the obtusely deltate-cordate blade ± 2.5 mm long, 2.4-2.8 mm wide; wings 4.8-6.8 mm long, the claw 1.5-3 mm, the oblong or lance-oblong blade 3.5-4 mm long, 1.4-1.8 mm wide; keel 6-8 mm long, the claws 2.2-3.2 mm, the obovate-elliptic blades 4-4.9 mm long, 2.1-2.8 mm wide; androecium 10-merous, 7-8.5 mm long, the longest filament free for it 2 mm; pod
obliquely obovoid, ±2.8 mm long, the style-base asymmetrically terminal, the valves hyaline in lower 2/3, thinly papery and pilosulous distally; seed ± 2 mm long. — Collections: 10 (iii).
Dry oakwoods, 1230-1900 m (± 4100-6350 ft), uncommon and of limited range, known only from valleys flowing w. and s.-w. from the massif of Nevado de Toluca towards Rio Balsas in s.-w. Estado de Mexico and immediately adjoining Michoacan.—Flowering October to January. —Material: Mexico: Chorrera, Temascaltepec distr., Hinton 2168 (K, MICH, NY, UC): Tejupilco, Temascaltepec distr., Hinton 1590 (GH, K, MICH, NY); 4 mi s.-w. of Temascaltepec, Gentry, Barclay & Arguelles 19,608 (RENNER, US); w.-s.-w. of Luvianos, Rzedowski 20,704 (ENCB); Canada de Nanchi- titla, Matuda 32,025 (MEXU); Valle de Bravo to Colorines, Ripley & Barneby 14,879 (NY); n. of Valle de Bravo, Ripley & Barneby 14,868 (CAS, DAO, GH, MEXU, MICH, US). Michoacan: Zitacuaro — Guanoro, Hinton 13,462 (K, MICH, NY, UC); Guanoro, Ripley & Barneby 14,801 (CAS, DAO, GH, NY, MICH, MEXU, US).
Dalea cuniculo-caudata (cottontail, of the softly silky, scut-like spikes) P. G. Wilson, Kew Bull. 1958: 158. 1958. — Mexico. State of Mexico: District of Temascaltepec; Mina de Agua, 1990 m, "pine woods", 31 Oct. 1932, G. B. Hinton 2333 (type)...." — Holotypus, K! isotypus, GH! paratypi, Hinton 1590, 2168, 13,462, cited above.
In the protologue D. cuniculo-caudata was compared with D. zimapanica, which is admittedly similar in form and coloring of the glabrous foliage but differs greatly in being a truly shrubby species with deciduous bracts and yellow flowers. In growth-habit D. cuniculo-caudata suggests the blue-flowered D. pectinata and its allies among which D. pulchella and D. mcvaughii, both distantly allopatric in Jalisco and northward along Sierra Madre Occidental, are technically most similar in their relatively few leaflets or dense spikes. The strongly verruculose stems of D. pulchella and its almost round, distant little leaflets of thick texture are decisively different. The calyx of D. mcvaughii is externally glabrous below its fringed orifice, and the petals lack subterminal glands. In its internally sericeous bracts D. cuniculo-caudata differs from all Pectinati except the habitally dissimilar D. virgata. The narrow range of D. cuniculo-caudata lies just within the periphery of that of the widely dispersed D. polystachya, which is (or can be) similar in habit of growth and is found in flower at the same season and in the same environment, sometimes sharing the same hillside. Differential characters of D. polystachya are the more numerous (in cauline leaves ± 12-20 not 6-12 pairs), flat rather than boat-shaped leaflets, deciduous bracts glabrous within, and less dense spikes of usually less densely pubescent calyces. Compare Plates LXVII and CVII. A notable field-character of D. cuniculo-caudata is the brittleness of the stems; unlike those of related species known to me in the living state they snap off abruptly when picked or when folded to lay away in press.
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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