Marina unifoliata (B.L.Rob. & Greenm.) Barneby

Authors

Rupert C. Barneby

Authority

Barneby, Rupert C. 1977. Daleae Imagines, an illustrated revision of Errazurizia Philippi, Psorothamnus Rydberg, Marine Liebmann, and Dalea Lucanus emen. Barneby, including all species of Leguminosae tribe Amorpheae Borissova ever referred to Dalea. Mem. New York Bot. Gard. 27: 1-892.

Family

Fabaceae

Scientific Name

Marina unifoliata (B.L.Rob. & Greenm.) Barneby

Type

based on Dalea unifoliolata Robins. & Greenm. Proc. Amer. Acad. 29: 383. 1894. max. pro parte (exclus. Mueller 663). — "...in dry, thin soil, barranca of Tequila, Jalisco, by Mr. Pringle, 6 October, 1893 (no. 4585)." — Lectotypus (Rydberg, 1919, p. 60, by

Synonyms

Dalea unifoliolata B.L.Rob. & Greenm., Parosela unifoliata (B.L.Rob. & Greenm.) Rose

Description

Species Description - Slender annual herbs (1) 1.5-4.5(5) dm tall, either simple and erect or more often branching from near the base, the branches divaricate and then incurved-ascending, commonly longer than the primary erect axis, glabrous up to the finely pilosulous inflorescence, the wiry, terete, stramineous or purplish, finely punctate and distally micro-tuberculate stems floriferous nearly throughout or at least from the middle upward, the peduncles mostly leaf-opposed, the large, solitary, terminal leaflets bicolored, green above, pallid beneath, lineolate both sides; leaf-spurs up to 0.5 mm long; stipules triangular-subulate, 0.3-1 mm long, their margins minutely gland-fimbriolate; intra- and post-petiolular glands forming a triad of purple grains at apex of petiole; leaves 7-30 (35) mm long, the petiole 1.5-16 mm long, subterete, minutely glandular, the petiolule inserted behind the lower margin of the terminal leaflet (this hence sub- peltate), the flat blade broadly ovate-deltate, suborbicular, or broader than long and therefore subreniform, truncate at base, very obtuse to openly emarginate at apex, 5-23 mm long, 5-25 mm wide, its prominent costa giving rise on each side to 8-18 parallel, divaricate secondary veinlets, its margin finely crenulate and charged with glands at first prominent but finally impressed; peduncles wiry, 0.5-3 cm long; racemes loosely (7) 10-35 (40)-flowered, the flowers ascending, the pilosulous axis becoming (1) 1.5-8 cm long; bracts caducous from a decurrent spur, submembranous, lance-acuminate beyond the cuneate base, (1.3) 1.9-2.6 mm long, their margins ciliolate and gland-pectinate below the middle, subglabrous dorsally; pedicels flexuously ascending, very slender, 0.6-1.4 mm long, charged at apex with a pair of grainlike glands; calyx 3-4 mm long, pectinately ciliolate along the sharply prominent ribs and the margins of the teeth with stiff, spreading-incurved hairs up to 0.2-0.3 mm long, the tube 1.5-1.8 mm long, the recessed, submembranous intervals charged with a chain of 6-7 transparent, elliptic glands, the lanceolate, plane, green teeth subequal, 1.5-2.3 mm long, but the ventral pair united behind the banner through nearly half their length, the margins of each tooth charged on each side with 1-2 minute glandular teeth and gland-tipped; petals bicolored, the banner whitish, early rubescent, the inner pairs magenta-purple, all eglandular, the inner perched at nearly the same level 1.1-1.5 mm above hypanthium rim, the keel-blades narrowly imbricated and adherent; banner spatulate, 2.2-3 mm long, strongly curved backward distally, the claw 0.5-0.9 mm long, the blade nearly as broad as long, obtusely 4-lobed; wings 3.5-5 mm long, the claw 0.6-0.8 mm, the blade obliquely obovate, 3-4.5 mm long, 1.9-2.8 mm wide; keel usually a trifle longer than wings, 3.8-5.2 mm long, the claws 1-1.3 mm, the broadly obovate blades 2.9-4 mm long, 2.1-3.4 mm wide; androecium 10-merous, 4.3-5.5 mm long, the longer filaments free for 1.1-1.4 mm, the connective glandular, the pale bluish anthers 0.35-0.45 (0.5) mm long; pod obliquely obovate in profile, strongly compressed, 2.1-2.5 mm long, constricted at the dorsal pore, the style-base terminal but excentric, the prow slenderly keeled, the valves firm beyond the hyaline base, thinly pilosulous distally, charged with 2 crescents of blister-glands. — Collections: 12 (ii).

Distribution and Ecology - Open or brushy grasslands, in thin oakwoods or in oak-juniper woodland, descending into ipomoea-thorn-forest, 500-1650 m (± 1650- 5500 ft), local but forming colonies, widely dispersed from s.-e. Mexico and adjoining Guerrero w. through the Balsas Depression and foothills of Sierra Madre del Sur to s. Jalisco; perhaps somewhat isolated in valley of Rio Grande de Santiago in w. Jalisco. — Flowering September to January.

Discussion

(Plate XX)

This species and M. greenmaniana together differ from all other described marinas in their unifoliolate leaves; from one another they differ in size of all their parts, M. greenmaniana being as it were a diminished version of M. unifoliolata, with this further difference, that the androecium is reduced from ten to nine members. The protologue of Dalea unifoliolata was based on a mixture of the two species, an error of judgment very natural at the time. Among numerous subsequent collections no morphologically intermediate forms have as yet been discovered, and the ranges of the two entities seem to be distinct, although they are nearly in contact in extreme southern Mexico state. Despite the similarity in general form, I believe they represent discrete, geographically vicariant species.

Growing and flowering among the drying weeds and yellowing grasses of late summer and fall, the plants of M. unifoliolata and M. greenmaniana are well camouflaged by the wiry fineness of their stems and by the attitude of the leaf-blades, which are tilted edgewise to the zenith like diminutive platyopuntia pads and present to the eye only a thin line, often tinged with purple. In the early morning hours, however, before the fleeting purple sparks of the petals have fallen to the ground, the plants may be picked out readily enough.

Distribution

Jalisco Mexico North America| Michoacán Mexico North America| Mexico North America|