150.  Dalea foliolosa (Aiton) Barneby

(Plate CXXXV)Annual herbs, variable in stature and habit, (0.5) 1-10 (12) dm tall, glabrous below the inflorescence, either branching from the base, the stems then diffuse and assurgent, or simple and paniculately branching from near or well above the middle, the stems reddish or stramineous, smooth or commonly sparsely verruculose distally, the foliage green, the leaflets smooth above, usually punctate dorsally and marginally but the glands sometimes obscure or lacking; leaf-spurs very short; intrapetiolular glands small, sometimes impressed or obscure; post-petiolular glands prominent; main cauline leaves 1-8 cm long, subsessile or shortly petioled, the rachis narrowly thick-margined, usually punctate, the leaflets (5) 7-17 pairs, elliptic, oblong-obovate, or oblanceolate, obtuse, obtuse and gland-mucronate, or rarely acutish, flat or boatshaped but not strongly folded, (1) 1.5-8 mm long; peduncles both terminal and leaf- opposed, slender but stiff, commonly erect, (1) 1.5-12 (16) cm long; spikes moderately dense, the calyces at anthesis subcontiguous but not compacted into a conelike head, at first ovoid to shortly oblong becoming oblong to cylindric, without petals 6-11 mm diam, the hispidulous axis becoming (4) 6-30 cm long, the lowest flowers declined or deflexed in fruit; bracts completely enveloping the young flower-buds but early thrown off, glabrous within and without, the circular or very broadly ovate, ovate-elliptic, flabellate, or obcordate body (1.7) 2-3.3 mm long, membranous at base and broadly hyaline-margined, sparsely glandular-verruculose dorsally, abruptly contracted into a subulate tail from 1/4 to nearly as long; calyx 2.9-6.7 mm long, sessile or elevated on an obscure pedicel up to 0.3 mm long, densely silky-pilosulous externally, the tube 1.9 -2.7 mm long, not recessed behind the banner, the slender ribs usually livid, becoming prominent in age, the membranous intervals glandless or charged with one vertical row of ± 3-5 small, transparent or pale yellow glands, the teeth varying from deltate to deltate and long-aristate, the dorsal one 0.7-4.3 mm long, varying from much shorter to nearly twice as long as the tube; petals variable in color, the banner usually opening white in part (the tip and basal lobes variably colored) but rubescent in age, the inner petals (elevated ± 0.7-1.4 mm from hypanthium rim) dull rose-pink to bright reddish-purple, magenta-purple, or vivid violet, usually all eglandular but sometimes gland-tipped; banner 2.7-4.5 mm long, the claw 1.2-2.8 mm, the broadly deltate- or hastate-ovate blade thickened at base but obscurely if at all recessed into a cornet, 1.3-2.8 mm long; wings 2.3-4.6 mm long, the claw 0.5-1.7 mm, the oblong-elliptic blade 1.6-3.5 mm long, 0.7-1.8 mm wide; keel 2.8-4.8 mm long, the claws 0.7-1.9 mm, the obliquely obovate to elliptic blades 2-3.5 mm long, 1.6-2.1 mm wide, united by their exterior edges; androecium (9) 10-merous, 3-4.8 mm long, the longest filament free for ± 1 mm, the connective gland-tipped, the anthers 0.2-0.4 mm long; pod obovoid-truncate, compressed, 2-2.6 mm long, slenderly crested dorsally, the ventral suture subfiliform but the prow greatly thickened, the style-base latero-terminal, the valves hyaline in the lower half, thence thinly papery, pilosulous, eglandular; seed (1.4) 1.6-2 mm long; 2n = 14.

The toronjil, so called in Guatemala and southern Mexico because of the penetrating smell of lemon-blam (Melissa) exhaled by the crushed leaves, is second only to D. leporina the most widely dispersed annual dalea of the plateau, temperate highlands, and interior subtropical valleys of Mexico, extending from Chihuahua and southern Coahuila to Chiapas, and thence on through mountainous Guatemala into Honduras, reappearing locally, probably as an alien, in Venezuela and Colombia. It is distinguished from other annual daleas with glabrous foliage and silky spikes by the suborbicular, hyaline-margined bracts which envelop the flower buds but are thrown off as the corolla begins to expand, and by the wide, bluntly thickened prow of the pod. As interpreted here, D. foliolosa is polymorphic and composed of numerous geographic races, collectively equivalent in scope to Parosela XVI. Citriodorae of Rydberg (1920, pp. 80-81), who recognized five species within the group. Variable features of D. foliolosa sens. lat. which seem to serve taxonomic purposes are the average stature of a population, the mode of branching, the length of the calyx-teeth, and color of the inner petals. The type encountered almost exclusively on the Mexican plateau, northward from the Valley of Mexico, is a low, slender plant with several diffuse stems (up to ± 3 dm) from the root-crown, calyx-teeth deltate and tipped with a small callous point, and petals opening dull rose-color and drying purplish or purplish- brown. This is the original Psoralea foliolosa of Aiton and probably also the plant sent by Sesse from Mexico as Psoralea citrodora and grown in the Madrid garden, the Psoralea citriodora of Cavanilles. In the valleys of the Lerma-Santiago and Balsas rivers, mostly below 1800 m (6000 ft), D. foliolosa is represented by a series of taller types, characteristically erect and monopodial, up to a meter tall, and paniculately branching beyond the middle into a flat-topped or broadly rounded panicle. Generally associated with increased stature one finds the calyx-teeth drawn out (the dorsal one especially) into a stiff, aristate spinule, and inner petals blue- or violet-purple drying blue. Here belong Parosela vernicia and P. citrina of Rydberg, which were separated on trivial and obviously variable characters involving shape of the leaflet-apex and length of the bracts’ acuminate tail. Easily separated in its extreme form from typical D. foliolosa this tall lowland form extends north discontinuously along the east slope of the plateau from Puebla to southern Tamaulipas (Jaumave), and reappears in central Oaxaca, in Chiapas, at 200-480 m in the Zacapa desert in Guatemala, and as a weed in northern South America. Unfortunately, however, numerous collections do not fit neatly into either category. When much material is brought together, the mucro on the teeth of typical D. foliolosa can be seen to elongate by tiny successive steps into a spinule of the sort designated below as the chief diagnostic feature of var. citrina. The monopodial, distally branching growth-form sometimes occurs in short-calyxed plants as little as 1 dm tall. And occasional populations include individuals with dull rose petals among the lively purples. The picture of variation is further complicated by the existence in southeastern Mexico, Guatemala, and Honduras, mostly at montane levels, of a form in which the short-toothed calyx of the Plateau var. foliolosa is combined with diffuse growth-habit and bright violet flowers of a hue matched at lower elevations in the same region by typical var. citrina. This southern type, which I interpret as a geographic variant of var. foliolosa too poorly marked to deserve nomenclatural status, has been described as Parosela roseola Rydb. and probably also, much earlier, as D. platystegia Schauer. It is often intuitively recognizable, but when studied in detail is found to possess no one technical character which does not occur (even though much less often) in what is believed to be typical var. foliolosa of the Meseta Central.