Pseudonemacladus oppositifolius (B. L. Rob.) McVaugh

Pseudonemacladus oppositifolius (B. L. Robin.son) McVaugh, comb. nov.
Nemacladus opposilifolius B. L. Robinson, Proc. Am. Acad. 26: 168. 1891. Bailea oppositifolia Greene, Erythea 1: 238. 1893.
Whole plant glabrous; stems one or several, herbaceous, erect or decumbent from a stout woody caudex, simple or with few ascending subordinate lateral branches, up to 2 mm. in diameter at base, green, 20-60 cm. high, with prominent narrow wings from the dccurrent petioles; leaves all cauline, mostly opposite or the upper alternate, the principal ones from few to 20, nearly all crowded into the lower third of the plant, thin and papery when dry, the margins sharply serrate with 4-9 teeth per cm., the teeth deltoid or narrow, sometimes almost setaceous, the blades ovate, rounded at base or the narrower ones cuncate, acute at tip, 1.0-1,5 cm. broad, 1.7-3.0 cm. long, with distinct, narrowly margined petioles 0.3-1.0 cm. long; tufts of slightly smaller leaves often present in the axils of the principal leaves; inflorescence 5-18 cm. long, 5-30-flowered, seemingly not at all secund, the stem leafless below it for 2-6 cm.; pedicels ascending, stiff, 3-5 mm. long in fruit, smooth or minutely glandularciliate near summit, each with a pair of bracteoles near the summit, these linear, entire, 1-2 mm. long, flat and more or less appressed to the hypanthium, decurrent into wings on the pedicel; flower-bracts linear to subulate, entire or the lowest toothed, 2.5-3.5 mm. long, decurrent into narrow conspicuous green wings on the stem; flower 6-7 mm. long; corolla 4-5 mm. long, glabrous except for the lower lip, which is pubescent within at base, the tube 1.01.7 mm. long, measured to the sinuses alternating with the three upper lobes, the two dorsal lobes (these corresponding to the lobes separated by the dorsal sinus in the genus Lobelia) forming a distinct lower lip about 4 mm. long, the free part of the lobes elliptic, acute, 1.2 mm. wide by 3.0 ram. long, the three upper lobes about equal in size and shape, narrowly triangular or elliptic, acute, about 1 mm. wide at base by 3 mm. long; color not certainly known, but lobes of lower lip thickened at the sinus between them, with an (apparently) yellowish callosity at this point; filaments 3.2-4.5 mm. long, coherent into a tube above for about half their length, somewhat pubescent below and adherent to the corolla-tube; filament-tube curved toward the lower lip, sharply recurved near tip so that the inclosed style-tip makes a U-shaped bend and points toward the base of the flower; anthers 0.6-0.7 mm. long, minutely roughened or viscid on back along the midline; hypanthium in anthesis campanulate, in fruit little changed in shape but slightly enlarged, nearly or quite as broad as high, 2-2.5 mm. across; capsule half inferior or slightly less, 3.2-3.7 mm. long; calyx-lobes linear-oblong or narrowly triangular, entire, 1.6-2 mm. long, subacute; seeds smooth, shining, ellipsoid, somewhat flattened, 0.60.7 mm. long.
Type locautv: Dry calcareous bluffs near Cardenas, San Luis Potos!, Pringle 3300 (Gray!). Distribution: Eastern San Luis Potosi; Hidalgo.