(Plate XCI)

Diffuse, polypodial, herbaceous or weakly suffruticose perennial herbs, the radiating, stramineous, livid, or castaneous stems branching at and beyond the middle, 2-6 dm long, charged distally with at least a few and often many small protuberant orange glands, variable in pubescence but never wholly glabrous below the spikes, the foliage often glabrous or nearly so, but the main cauline leaves sometimes green and contrasting with silvery-pilose leafy spurs developed low on the plant at late anthesis, rarely pilosulous throughout with widely spreading spiral hairs up to 0.4-0.8 mm long, always residually pilosulous on the peduncles, the rather thick-textured leaflets conspicuously punctate beneath and often more faintly so above; leaf-spurs 0.6-1.5 mm long; stipules lanceolate or lance-caudate, papery or early becoming so, often castaneous, (2) 3-6 mm long, commonly glabrous or nearly so dorsally; intra- petiolular glands small, hemispherical; post-petiolular glands prominent, orange or fuscous, obtuse or mammiform; main cauline leaves 1-4.5 cm long, shortly petioled or subsessile, with narrowly margined rachis and 4-8 pairs of oblong-oblanceolate, -elliptic, or -obovate, obtuse to subemarginate but often bluntly gland-mucronulate, boat-shaped, loosely folded, or marginally involute leaflets (1.5) 2.5-9.5 mm long; peduncles terminal to all branchlets, 1-9 (12) cm long; spikes very dense, conelike, ovoid or subglobose becoming ovoid-oblong, without petals 8-14 mm diam, the pilosulous axis becoming 0.7-2 cm long; bracts persistent, dimorphic, the outermost ovate- to broadly lance-acuminate, glabrous except at very base, thick-textured throughout, the inner ones oblanceolate, pallid and thin-textured at the narrow base, herbaceous, livid-castaneous, gland-charged and dorsally pilosulous distally, the tip often glabrate, glabrous within; calyx (3.7) 4-5.7 mm long, pilosulous throughout with fine, spreading hairs up to 0.3-0.7 mm long, the tube (sometimes glabrescent at base) rather narrowly campanulate, recessed ± half its length behind the banner, 2.5-3.6 mm long measured to a dorsal sinus, the ribs slender, pale, becoming prominent only in fruit, the membranous, pallid intervals charged with (1) 2-5 (7) small, orange or colorless glands, the triangular or (when short) deltate, short-acuminate, gland-spurred, livid teeth a little unequal, the dorsal one 1.1-2.7 mm long (0.5-2.5 mm shorter than the tube), the ventral pair a little shorter and broader; petals opening bicolored, the banner sometimes colored at base and tip of blade but largely white, rubescent in age, the inner ones blue or purple, raised only 1-2.4 mm above the hypanthium rim, usually all glandless but the banner sometimes gland-tipped; banner 6.5-10 mm long, the claw 3.5-4.1 mm, the ovate-cordate or suborbicular, emarginate, gently recurved blade 3.6-6 mm long, 3.2-4.8 mm wide, closed at base into a comet-like well; wings 5.6-6.6 mm long, the claw 1.7-2.2 mm, the oblong-oblanceolate or lance-oblong blade 4-5.8 mm long, 1.5-2.3 mm wide; keel 7.4-10.5 mm long, the claws (2.6) 3-4.2 mm, the broadly oblanceolate to oblong-obovate blades 4.8-6.5 mm long, 2.4-3.3 mm wide; androecium 7.2-9.2 mm long, the longest filament free for ± 2.4-3 mm, the anthers 0.55-0.7 mm long; pod obliquely obovoid, 2.3-2.9 mm long, the style terminal but excentric, the valves membranous, almost transparent, thinly pilosulous distally, the keels filiform, the dorsal one dehiscent in age, the seed 1.6-1.7 mm long.

The striking diagnostic features of D. cyanea are the relatively few leaflets, the sub- globose, conelike spikes, the dimorphic bracts, the deeply recessed adaxial sinus of the calyx, and the proportionately very large banner which nearly or quite equals in length the detached keel. In Rydberg’s monograph (1920, pp. 74, 86, 91) forms of the species are introduced in three places, under the names Parosela cyanea, P. pilosissima, and P. fissa, the two first figuring as types of monotypic sections, the third, misinterpreted as annual, associated with the entirely different D. polygonoides. Field experience in the Sierra Madre west of Ciudad Durango has shown the D. cyanea and P. pilosissima represent respectively less and more densely pubescent phases of one entity. The status of P. fissa, which is still known only from the two collections already available to Rydberg fifty years ago, remains controversial. It seems to be distinguished only by greater develop ment of the bracts and stipules and by pink-purple, not vivid blue petals.