Pediomelum reverchonii (S.Watson) Rydb.

Authority

Grimes, J. E. 1990. A revision of the New World species of Psoraleeae (Leguminosae: Papilionoideae). Mem. New York Bot. Gard. 61: 1-114.

Family

Fabaceae

Scientific Name

Pediomelum reverchonii (S.Watson) Rydb.

Description

Species Description - Single-stemmed, but much branched, erect, perennial herbs to 1.5 m tall, glandular throughout and pubescent with short, ascending-curved hairs, the stems arising from a deep woody muchbranched root, striate, basally somewhat pithy and with exfoliating scaly epidermis; cataphylls 5-15 mm, few on base and subtenanean part of stems, first 2-4 nodes usually lacking branches and with cataphylls. Stipules erect, linear to somewhat linear-lanceolate, 7-12 x 1-4 mm, papery, very sparingly strigose, obviously veined, the lower ones sometimes fused-free, free above, tardily deciduous. Leaves palmately 3(-4)-foliolate, lower ones caducous; leaflets commonly deciduous by fruiting; the petiole persistent only a short time longer, 0.2-4.0 cm, lightly canaliculate, sparingly short-ascending-pubescent, the base swollen but not of different color or texture, and not jointed to stem; petiolules 1.5-2 mm, blond, slightly swollen and usually more densely pubescent than petiole; leaflets narrowly elliptic, 1.3-4.3 X 0.3-1.2 cm, apiculate, at base obtuse to slightly cuneate, glabrous and black-glandular on upper surface, lower surface uniformly shorttomentose and sparingly black-glandular. Inflorescence a modified pseudoraceme with two nodes and (1-)3 flowers per node, the missing flowers sometimes rudimentary; peduncle 1.4-1.6 cm; rachis 5-7 mm, internodes to 7 mm; bracts persistent, often marcescent, orbicular and cuspidate to caudate, 7-14 x 6-13 mm, short-pubescent and densely dark brown- to black-glandular, persistent; pedicels 3.5-5 mm. Flowers 14-20 mm; calyx short-pubescent and densely glandular, 10-12 mm long to upper tooth, 11-19 mm to lower tooth, the tube 4-5 mm, the upper teeth linear-lanceolate, 2.5-3 x 0.75-1 mm, the lateral ones linear-lanceolate, 6.5-7 x 1-1.5 mm, the lower tooth lanceolate, 10.5-12 x 2-3.5 mm, all with denser, slightly longer pubescence, internally minutely pubescent, the calyx in fruit strongly gibbose-campanulate, with veins to the apex of each tooth and to each sinus, those to the sinuses bifurcating and continuing as marginal veins about V2 the length ofthe tooth; petals lavender; banner oblanceolate, 13-16 x 6-7 mm. the broad claw 4-5 mm, the blade emarginate, biauriculate, the auricles internally callose; wings 12-14 X 3 mm, the claw 4-5 mm, the auricle to 1.5 mm; keel petals 8-10 x 2.5-3 mm , the claw 3.5-6 mm, the blade with darker blotch apically, sometimes somewhat apiculate; androecium 8-10 mm, anthers elliptic, 0.25-0.33 mm; gynoecium 8.5-9 mm long, ovary pubescent at apex, style pubescent at base. Fruit body obovate-elliptic in profile, 7-8 x 5 mm, vary sparingly pubescent at apex, densely glandular, the beak 3-4 X 3 mm, equal to or slightly longer than calyx teeth. Seed oblong-reniform, 6 x 4 mm, compressed but not flattened, red-brown.

Discussion

Lectotypus, Rocky prairies, Johnson Co., West Texas, June, /. Reverchon, G H ! isolectotypi C A S (probable)! F (2)! K! M O ! N Y (3)! U S (2) WIS! Syntypi, "Rocky prairies between the lower Cross Timber and the Brazos, Hood Co., [Texas], Aug 4 1877,/. Reverchon," G H ! M O ! N Y (2)! U S ! Ockendon (1965) noted that the holotype was at G H ; Rydberg (1919) said only that the type was from Hood County, Texas. T o dispel the confusion concerning the collections I a m clearly designating the June 1877 collection from Johnson County as lectotypus. Contrary to the note by Ockendon, Curtiss # 553 does not contain the syntypes, but does include collections of Pediomelum digitatum (Nutt. ex Ton. & A. Gray) Grimes.

Distribution

In open fields, prairies or scablands, usually in rocky to sandy granitic soils from ca. 200-500 m; in Munay, Johnston, Carter and Garvin cos., Oklahoma, and Cooke, Hood, Johnson, Montague, Parker and Wise cos., Texas. R.

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