Monographs Details: Bonnetia wurdackii Maguire
Authority: Maguire, Bassett. 1972. The botany of the Guayana Highland--part IX. Mem. New York Bot. Gard. 23: 1-832.
Description:Latin Diagnosis - Frutex vel arbor parva ad 10 m alta; ramisculis teretibus tenuibus; cicatricibus foliorum delapsorum late ellipsoidalibus cum fasciculatis vascularibus notatis; foliis alternatis, subsessilibus, glabris, integris vel minute denticulatis, imbricatis, laminis obovatis, subtus pallidis, stomatis minute punctatis, apicibus minute apiculatis vel retusiusculis; marginibus aliquantum involutis, costa prominenta, venis lateralibus obscuris; floribus solitariis, axillaribus, pedicellatis, 10-12 mm longis, supremis 4-6 bracteis foliaribus ferentibus; sepalis 5, quincuncialibus, lanceolatis, 7-9 mm longis, 3-4 mm latis; petalis 5, obovatis, 10-12 mm longis, 7-9 mm latis, flavidis; staminibus numerosis, filamentis liberis, ca 2 mm longis; antheris 4-thecatis, ca 0.7 mm latis, 0.5 mm altis; pollinibus tricolporatis, diam polari ca µ 40, diam aequatorio ca µ 40; ovario 3-loculari; placentatione axillari, 4-seriata; ovulis numerosis; stylis teretibus, ramis liberis, ca 2 mm longis; stigmatibus distalibus brevi-papillato-hirsutis; capsulis seminibusque ignotis.

Distribution and Ecology - Distribution. Known only from the summits of Chimantá-tepuí as follows.


Type. Tree 4-10 m high, flowers yellow, frequent in lower part of lower west cumbre, Churí-tepuí (Muru-tepuí), Chimanta Massif, at 2100-2200 m alt, Edo. Bolívar, Venezuela, 24 Jan 1953, John J. Wurdack 34181 (holotype NY).

Bonnetia wurdackii, seemingly restricted to the Chimanta complex, occurs in the summit areas where its more widespread close relative, B. roraimae, is found. The latter throughout its range often gives dominance and character to dwarf summit forests. The two species on Chimanta seem to be clear-cut and to resist interbreeding. One specimen, however, Steyermark & Wurdack 633, seems to be intermediate between the two species, indicating a possible cross. The leaves of Steyermark & Wurdack 633 have the leaf form of B. roraimae, but lack the striking bronze and silvery coloration which gives B. roraimae its extraordinary full-crowned elegance. The collection in question has the flower color and form of B. wurdackii, and bears mature capsules which are not found in the other cited collections. Capsular description of Steyermark & Wurdack 633 follows: capsule flask-shaped, inclusive of the styles ca 8 mm long, dehiscing septicidally, 3-locular, exocarp separating from endocarp; placentation axillary, 3-4-ranked, especially below, funiculus ca 0.5 mm long, ascending; seed ascending, numerous, falcately lanceolate, narrowly wing-margined at the distal end, ca 2 mm long; embryo not seen.