129.  Dalea botterii (Rydberg) Barneby

(Plate CXIV)

Shrubs up to 1.2 m tall, paniculately branched distally, the older stems brown, tuberculate, glabrous or glabrescent, the young branchlets purplish, villosulous, the foliage varying from glabrous to thinly pilosulous, the leaflets glabrous both sides, or above, or thinly hairy both sides, green or subglaucescent, prominently black-punctate beneath; leaf-spurs 0.8-2 mm long; stipules lanceolate to narrowly triangular, (1) 1.5-5.5 mm long, usually purplish, glabrous or glabrate; intrapetiolular gland 1, small; post-petiolular glands prominent, usually livid, globose or conic; main cauline leaves 2-3.5 cm long, shortly petioled, with smooth, scarcely margined rachis and 7-13 pairs of leaflets varying in shape and number according to the variety (defined below); peduncles terminal to branches and to some lateral spurs, 0.3-2 cm long; spikes many-flowered, moderately dense (flowers 2-3-ranked when pressed), narrowly pyramidal becoming cylindric, without petals 12-15 mm diam, the villosulous axis becoming 1-7 cm long; bracts persistent, ovate- to lance-acuminate or -caudate, firmly papery, livid-castaneous or blackish, either quite glabrous dorsally or ciliolate about the keel and tail, often thinly tuberculate; calyx 4.7-8.2 mm long, the tube 2.4-3.1 mm long, glabrous or nearly so in the lower 1/3-2/3, thinly pilosulous distally, like the teeth, with spreading-ascending hairs up to (0.4) 0.5-0.9 mm long, the stout ribs castaneous, the intervals firm, charged with 2-5(6), usually black or livid blister-glands, the mouth oblique but not recessed dorsally, the teeth unequal, the dorsal one longest, varying from 0.3 mm shorter to 2.4 mm longer than the tube, all 5 triangular-acuminate or -aristiform, gland-spurred; petals concolorous, violet- or indigo-purple, drying rose- brown to black, the banner and keel gland-tipped, the banner often charged with a gland-crescent, the wings and keel elevated ± 1.1-2.4 above the hypanthium; banner (5.6) 6.2-7.5 mm long, the suborbicular blade 3-4.4 mm long, (3) 3.4-5 mm diameter, recessed into a comet at base; wings 5.6-7.8 mm long, the claw 1.6-2.4 mm, the oblong-oblanceolate blade (4.2) 4.6-6 mm long, 1.8-2.6 mm wide; keel 7.3-10.7 mm long, the claws 2.6-4.7 mm, the blades 5.1-7.4 mm long, 2.9-4 mm wide; androecium 6.8-11 mm long, the longest filament free for 2.4-3.5 mm; anthers 0.6-0.8 mm long.

The syndrome of characters that distinguishes D. botterii is the shrubby growth-habit combined with persistent, livid or blackish bracts glabrous or nearly so dorsally, a calyx hairless toward the base of the tube but villosulous about the mouth and teeth, and petals of some shade of violet or indigo-purple that turns rose-brown to black when dried. Except for the color of the petals D. botterii cannot well be told apart from the sympatric D. lutea. Possibly it may consist of several mutually independent color-variants of the latter species. At present we have no evidence bearing on the point, and as there is no other known instance of purple flowers and yellow flowers existing in the same species of Dalea, it seems prudent, pending analysis of the pigments, to maintain D. botterii as distinct. I have not seen the fresh flower of var. atrocyanea; its black coloring hardly differs when dry from that seen in some strains of D. lutea which are known to have been yellow when fresh, but in the buds traces of indigo-blue can be seen. The petals of var. botterii, at least on the Cumbres de Acultzingo between Tehuacan and Orizaba, where the species was first collected by Liebmann in 1841, are violet and concolorous. The color is perceptibly different from any of the pink-purples prevalent among Mexican shrubby daleas similar in other respects, all of which have a banner white or yellowish in bud and early anthesis.

When Rydberg described Parosela botterii and P. atrocyanea, he had only one collection of each for comparison, and he separated them in terms of pubescence characters which subsequent experience has shown to be unreliable. They are similar in all essential features, but do seem to differ in number and shape of leaflets, in length of calyx-teeth, and in size of the corolla. They appear, moreover, to be vicariant in range, and are treated below as geographic varieties.