113.  Dalea macrotropis Schauer

(Plate CIV)

Apparently suffruticose and diffuse, the slender, procumbent, arching but not (?) radicant stems at least 3 dm long (full stature unknown), livid-castaneous, glabrous,

prominently verruculose, the foliage dimorphic, the primary cauline leaves glabrous, with thick-textured, glaucescent, dorsally dotted leaflets, these subtending ± densely puberulent short-shoots composed of smaller crowded leaves densely pilosulous- tomentulose with spreading hairs up to 0.4 mm long; leaf-spurs 0.5-0.7 mm long; stipules slenderly subulate, 1-1.4 mm long, livid, glabrous; intrapetiolular glands small, prominent; post-petiolular glands mammiform; leaves short-petioled, the primary cauline ones 12-16 mm long, with narrowly margined, punctate rachis and 5-8 pairs of oblong-oblanceolate to narrowly obovate, emarginate, dorsally keeled, loosely folded leaflets 2.5-5 mm long, the leaves of short-shoots smaller, with 3-5 pairs of shorter leaflets; peduncles terminal to main stem and branches, 2-4 cm long, puberulent under the spike; bracts deciduous, ovate-acuminate, livid, ± 3 mm long, flat, the lowest glabrous or nearly so dorsally, the interfloral ones pubescent at base dorsally, glabrous distally, all silky within; calyx 4.8 mm long, thinly pilosulous with ascending hairs up to ± 0.35 mm long, the tube 2.6 mm long, not recessed behind banner, the orifice subsymmetrical, the ribs castaneous, becoming prominent, the membranous intervals charged with 1 row of ± 4 small glands, the subulate teeth a little unequal, the dorsal one 2.2 mm long, the ventral pair a little shorter and broader, none gland-spurred; petals bicolored, the banner whitish or yellowish on opening, the epistemonous ones perched 0.6-1.4 mm above hypanthium rim, rose-purple, none gland-tipped but the banner charged in eye of blade with a few tiny glands; banner 6.5 mm long, the claw 3.3 mm, the deltate-cordate, hooded blade open at base, ±3.5 mm wide and long; wings 6.3 mm long, the claw 2.5 mm, the oblong-obovate blade 4.4 mm long, 1.9 mm wide; keel 9 mm long, the claws 4.1 mm, the broadly ovate-elliptic blades 5.5 mm long, 3.1 mm wide; androecium ± 8 mm long, the connective gland-tipped, the anthers 0.5-0.55 mm long. — Collections 1 (o).

Range and habitat unknown, the description based on the following specimen: "Mexico, Aschenborn, Schumann", the ticket with figure "43" in lower left corner and stamped "Mexico leg. Schmitz.", W (herb. Rchb. f., no. 125116).

Dalea macrotropis (with large keel) Schauer, Linnaea 20: 742. 1847.— "In montanis Oaxacanis. Aschenb[orn] n. 311." — Holotypus, presumably destroyed at B; no isotypus found, v. discussion below.

The description of D. macrotropis has been prepared from a fragmentary but unique specimen, the only one examined that agrees in almost all points with the protologue. Schauer’s description is admirably detailed and includes measurements of leaves, leaflets, calyx, and keel-blades, all agreeing with the plant at Vienna. The most unusual characteristic of Schauer’s plant was the distribution of the vesture: "glabra, solis innovationibus sericeo-villosis." This phrase aptly describes the densely silky axillary short-shoots that arise from glabrous stems and are subtended by glabrous primary foliage. The only discrepancy between description and plant is a slight and unimportant one; according to Schauer the leaflets should be 7-10 pairs; in the specimen seen they are 5-8 pairs.

Interpretation of the label is difficult. The handwriting is unknown to me and it is not clear whether the plant was collected by Schmitz (as stamped) or by Aschenborn (or Schumann) as given by what seems to have been the original ticket. It is not possible to link the specimen securely with Aschenborn 311, the lost holotypus of D. macrotropis, but its characters suggest that it is indeed an isotype. No modern collection in American herbaria matches it and if this is not Schauer’s plant it must represent an undescribed entity.

I speak of D. macrotropis as an undescribed entity rather than in terms of a distinct species, for this is not securely demonstrated by the scanty material available. Under the title of D. aemgma, immediately foregoing, I have described a plant from the plateau north and east of Mexico City which seems closely related to D. macrotropis, but has all foliage like the stems equably pilosulous, a much more densely pubescent calyx, and bracts of different shape. These differences might well dwindle into insignificance if we had more extensive material. The only Mexican dalea characterized by glabrous primary leaves subtending gray-villous short-shoots is D. hemsleyana, an erect shrublet with extremely compact and hard conelike spikes, differing further in small details of interfloral bracts and a glandless banner. The Vienna specimen does not fit easily into my concept of this species but I suspect they are close allies. In the circumstances D. macrotropis remains as a shadowy concept, its name and status contingent on discovery of an authentic piece of Aschenborn 311 in some herbarium and a matching population somewhere in highland Mexico.