Gleasonia duidana Standl. var. duidana
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Authority
Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.
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Family
Rubiaceae
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Scientific Name
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Description
Distribution and Ecology - Upper slopes and summits of sandstone table mountains of southern Venezuela. VENEZUELA. Amazonas: Cerro Duida, "The Valley," summit, alt 1500 m, 26 Nov-16 Dec 1928, Tate 467 (holotype NY); Central Camp, alt 1440 m, Tate 1026; summit along valley forest between Central Camp and Brocchinia Hills, alt 1675 m, Steyermark 58098; north slopes and ridges of Cano Negro basin, summit, alt 2000-2300 m, Maguire, Cowan & Wurdack 29711; Cerro Camani, upper slopes, alt 1800 m, Maguire. Cowan & Wurdack 81800; Cerro Guanay, woodland between Campo Verado and Campo M. Perez, alt 900-1100 m, Maguire, Phelps, Hitchcock & Budowski 31680; Cerro Sipapo (Paraque), low bush bordering Savanna Creek, alt 1500 m, Maguire & Politi 27579; marsh around pool near Camp Savanna, alt 1500 m, Maguire & Politi 27712; brakes below escarpment, Camp Savanna, alt 1500 m, Maguire & Politi 27564; Cerro Huacha-macari, cumbre between Summit Camp and East Ridge savanna, alt 1800 m, Maguire, Cowan & Wurdack 30032, 80043; Cerro de la Neblina, banks of Canon Grande east of Cumbre Camp, alt 1100 m, B. & C Maguire, Wurdack & Keith 42205; Bolivar: Chimanta Massif, dwarf forest on semi-open shoulder of northwestern part of Abacapa-tepui, alt 1400 m, Steyermark 75163; western part of Abacapa-tepui, alt 1250 m, Steyermark 75220; faldas del Cerro Apacara, Cardona 1947; slopes and talus forest, Sarven-tepui, between Camps 4 and 5, alt 1500-1750 m, Wurdack 34065.
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Discussion
Gleasonia duidana Standi. Field Mus. Publ. Bot. 7: 372. 1931.
Note: At the time of the original description, no fruit was known to Standley. The following description of the fruit is based on the collection of Maguire & Politi 27564 from Cerro Sipapo: Capsula loculicide dehiscens rhomboideo-suborbicularis atrobrunnea (1.8) —3— 3.5 cm longa (2.5) -3-4 cm lata verruculosa primum plus minusve pilosula demum glabrata fere ad basin fissa, apice truncata; seminibus in quoque loculo 15 crebris lateraliter compressis angulatis castaneis vel fuscis rhomboideo-quadratis 9-10 mm longis 8-9 mm latis (immaturis) valde concavis, testa e cellulis oblongis papillatis constanti. The var duidana is the commonest and most widespread variation of G. duidana, occurring on many of the sandstone cerros of the Venezuelan Guayana. but principally from the Chimanta Massif westward to Cerro Guanay and Sipapo southward to Cerro de la Neblina. The intergradations which are encountered between var duidana and the other varieties here recognized indicate that they may be best considered as varieties, with a tendency toward geographical segregation. In var duidana the inflorescence is more or less compact with the tertiary or ultimate branches of the inflorescence mostly suppressed or reduced to less than 2 cm long, the whole inflorescence measuring usually 5-7 cm high and 6-10 cm across, but exceptionally (Wurdack 34065 from Sarven-tepui) attaining a spread of 10 cm high and 15 cm across. The leaf-blades in var duidana are generally oblong or obovate-oblong, averaging 6-11 cm broad, but in Wurdack 34065 may attain 13 cm broad, thus intergrading into var latifolia. While most of the specimens of Wurdack 34065 have the leaves 6-11 cm long and are oblong-elliptic or oblong, one of the collections belonging to this number attains a length of 13 cm and is wider than the other duplicate collections. Similarly, variation is encountered on the lower leaf-surface of var duidana from mainly a slight development of pubescence with short, appressed hairs to glabrate to densely pubescent in the collections of Maguire, Coican & Wurdack 30032 and 30043 from Cerro Huachamacari. This strong development of pubescence is not so marked and is of a different type from that found in G. uaupensis Ducke. Standley states in his original description that the filaments are glabrous, but examination of many specimens shows that while some glabrity is present in the upper portion, the filaments are mainly sparsely to densely pilosulous in the upper half and densely pilosulous below. Standley also describes the anthers as “dorsi-fixed,” whereas actually they are dorsally versatile.
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Distribution
Upper slopes and summits of sandstone table mountains of southern Venezuela.
Venezuela South America|