Two New Subspecies of Hibiscus trilobus (Malvaceae) from Central and South America

Abstract

Hibiscus trilobus subsp. hirsutus from Belize and Guatemala is described as new, based on differences in pubescence, leaf form, and phytogeography. The new combination H. trilobus subsp. ingratus is also made, based on H. ingratus Miquel. A key is provided to distinguish the three recognized subspecies. In preparing a treatment of the Malvaceae for Flora Mesoamericana, the second author became aware that one taxon that pertains to the area, herein treated as a subspecies of Hibiscus trilobus Aublet, did not as yet have a name. Although the plant was recognized as distinct by Blanchard (1976), who treated H. trilobus as comprising three subspecies from Surinam, the Caribbean (Jamaica, Hispaniola, and Puerto Rico), and Central America (Belize and Guatemala), the names for these subspecies have not previously been effectively published. The present paper intends to rectify that omission and make the names available. Hibiscus trilobus subsp. hirsutus 0. J. Blanchard & Fryxell, subsp. nov. TYPE: Guatemala. Peten: La Libertad and vicinity, 10 May 1935, M. Aguilar 486 (holotype, NY; isotypes, F, F photo 56202, LL). Figure 1. Ab Hibisco trilobo subsp. trilobo et subsp. ingrato foliis minus profunde 3-5(raro 7)-lobis, indumento pilorum erectorum tenuium simplicium 2-4 mm longorum distinguendus, pubescentia densissima hirsuta petiolis pedicellis bracteis involucralibus et calyci dimidio inferiore. Shrubs or subshrubs 2 to 5 m tall, the stems with stout, often bulbous-based prickles, simple hairs 3 to 4 mm long, and also longitudinal lines of smaller, denser hairs. Leaves cordate, crenate-serrate, up to 14 cm long, 15 to 17 cm wide, broadly and shallowly 3to 5-angled or -lobulate (rarely 7-lobulate), acuminate, sparsely hirsute above and beneath with simple hairs 1 to 3 mm long, these denser on principal veins; petioles 5 to 12 cm long, hirsute, with occasional prickles, and with the adaxial side densely puberulent; stipules subulate, 4 to 5 mm long, hirsute. Peduncles solitary in the leaf axils, shorter than to longer than subtending petiole, lacking prickles, densely hirsute, these patent hairs 3 to 4 mm long; involucellar bracts ca. 14, 14 to 16 mm long in flower, to 25 mm long in fruit, linear, hirsute; calyx 2 cm long in flower to 5 cm long in fruit, + cylindric, prominently 20-ribbed, accrescent (inflated) in fruit, densely hirsute (hairs 2 to 4 mm long and spreading), the shallow lobes acuminate; petals 5 to 11 cm long, pink (yellowish in sicco) with darker base; staminal column ca. half length of petals, the anthers purplish; styles 5, essentially glabrous, with capitate stigmas. Capsules 2 to 3.5 cm long, enclosed in persistent calyx, hispid, these hairs 4 mm long; seeds 3.5 to 4 mm, short-pubescent, the hairs rusty-red. Two of the collections cited for Hibiscus trilobus subsp. hirsutus (Aguilar 486 and Proctor 30054) were originally distributed as Hibiscus diversifolius Jacquin, so additional duplicates of these collections might be found in other herbaria filed under the latter name. The distribution of the three subspecies, as indicated in the following key, is mapped by Blanchard (1976: 280, fig. 10), and a photograph of the holotype of H. trilobus subsp. hirsutus is reproduced (Blanchard, 1976: 346, fig. 43). Paratypes. BELIZE. Toledo, s.l., 25 Jan. 1929, Stevenson 88 (F); Cayo, Chiquibul Forest Reserve, vicinity of Caracol Ruins, in ruined Mayan reservoir, 1500 to 1700 ft., 24 Apr. 1969, Proctor 30054 (IJ, LL, MO). GUATEMALA. Peten: San Antonio, 13 km camino Libertad, Flores, 14 Feb. 1970, Tin Orttz 713 (MICH, US). NOVON 10: 190-192. 2000. This content downloaded from 157.55.39.186 on Tue, 11 Oct 2016 06:00:57 UTC All use subject to http://about.jstor.org/terms Volume 10, Number 3 2000 Blanchard & Fryxell Subspecies of Hibiscus trilobus 191