Mitracarpus frigidus (Roem. & Schult.) K.Schum. var. frigidus

Authority

Maguire, Bassett. 1972. The botany of the Guayana Highland--part IX. Mem. New York Bot. Gard. 23: 1-832.

Family

Rubiaceae

Scientific Name

Mitracarpus frigidus (Roem. & Schult.) K.Schum. var. frigidus

Type

Type. Silla de Caracas, Venezuela, Humboldt & Bonpland (Willd. herb. no. 2623).

Discussion

Mitracarpus frigidus (Willd. ex R. & S.) Schum., Mart. Fl. Bras. 6(6): 81. 1888.

The photo of the type in the Willdenow herbarium at B from the Silla de Caracas shows a plant with pubescent leaves and stems. This is matched by material from the type locality on the Silla de Caracas of Avila Mountain above Caracas by such specimens as Allart 45 and Hermanos Cristianos 131. Urban (Symb. Ant. 3: 387. 1903) also noted the pubescence of the Willdenow herb, type specimen as follows: “typus Willdenowianus (Herb. n. 2623 e Silla de Caracas) ramis pubes-centibus, foliis lanceolatis v. oblongis, 8-15 mm latis, supra brevissime pilosis, subtus breviter pubescentibus . . .

The pubescence varies on the stem from sparsely to more densely villous, and on the leaves from densely hirsutulous beneath on the surface as well as the midrib to less densely, and on the upper leaf surface from glabrous to densely substrigillose. The corollas vary from sparsely aculeate-hispidulous below the apex without to more puberulent and aculeate, while the upper portion of the hypanthium varies from densely hirsutulous to sparsely pubescent with fewer and less conspicuous pubescence. The pubescent variation of M. frigidus has mainly dimorphous sepals, the slightly shorter ones being subhyaline. The setae of the stipular sheath are mainly few (3 more or less) and glabrous, but in Pittier 7972 and 8011 from Edo. Carabobo the stipular bristles are more numerous and more pubescent, the leaves narrower, and the flowering heads with shorter corollas and calyx lobes.