Monographs Details: Epidryos guayanensis Maguire
Authority: Maguire, Bassett. 1965. The Botany of the Guayana Highland. Mem. New York Bot. Gard. 12 (3): 1-285.
Description:Latin Diagnosis - Herbae perennes epiphyticae; caudicibus brevibus nuUis ramosis, vel paucicipitalibus; foliis valde distichis; vaginis conduplicatis subinduratis vel papyraceis, conspicue venis, 12-18 cm longis, 2-3 cm latis, ventrale (laterale) essentialiter rectilinearibus, exauriculatis; pedunculis numerosis (8-11), 4-6 dm longis, filiformibus 0.4-0.5 mm diam, unisulcatis, 1-3 spiculatis; spieulis ca. 12 mm longis, sepalis inclusis; bracteolis gradatis, ca. 14, ovato-lanceolatis vel lanceolatis, valde seariomarginatis, 3-7 mm longis, exterioribus ovato-lanceolatis, interioribus lanceolatis, subhyalinis; sepalis 3, liberis, lanceolatis, ca. 10 mm longis, basibus hyalinis, 5-7-venis; petalis 3, anguste rhomboideo-lanceolatis, aliquantum carnosis; unguibus ca. 4 mm longis, ca. 1.5 mm connatis; staminibus 6, introrsis, filamentis 3-4 mm longis, ca. 0.4 mm latis, ca. 1 mm in cylindro connatis; antheris oblongolanceolatis ca. 2.5 mm longis, subsagittatis, 4-lobatis, evidenter 2-loculis, nonrugulosis, poro terminale dehiscente, lobis posterioribus hand productis; ovario 3-loculare, loculis pluriovulatis; stylo clavato, ca. 4 mm longo; capsulis ellipticoovatis, 7-8 mm longis, 4-5 mm latis, loculicidale dehiscentibus, exocarpo indurate endocarpo indurate separate; seminibus in sieco maturis prismatico-discoformibus 1.2-1.5 mm diam, nigrescentibus, axiale cum appendice alba testa producta.
Dispersal - Distribution. Known by the type collection from British Guiana, and from adjacent Venezuela by the following paratypes.
Discussion:Epidryos is unquestionably a derivative of Stegolepis, in large probability of the subsect. Ferruginea of the sect. Guianensis. There is habital similarity with the Ferruginea, and in Stegolepis choripetala we find a partial or almost complete separation of the endocarp of the capsule from the exocarp, a condition that prevails prominently and characteristically in all species of Epidryos.
This small segregate group is of especial interest geographically. It will be recalled that all twenty-three species of the basic genus Stegolepis are confined without exception (so far as known) to the sandstone region of Guayana. Of the small aggregate Epidryos, its three species are apparently quite localized in strikingly disjunct regions, viz., Panama, where E. allenii is narrowly endemic; Colombia, in the low-altitude, high-rainfall Pacific region of the Bay of Choco; and in the Pakaraima Mountains of British Guiana and adjacent Venezuela, the largest of the three disjunct areas (in part coincident with that of Stegolepis),from which there are now four ample and well prepared collections.
The mutual isolation of the three areas of occurrence, and the closeness of affinity that E. guayanensis holds with E. allenii of Panama, raise interesting questions of origin and dispersal of the three biologic elements. One wonders if they originated from the basic stock in Guayana, and then, by some random dispersal, found haven in isolated Panama and coastal Colombia. Or are they relictual of progenitors that were during pre-Andean or inter-Andean time widespread with continuous distribution.
The geographic compactness and restriction of Stegolepis would suggest the latter course of events. The sandstones of Guayana—or better the great lens of the Roraima sediments—have almost equally been reduced.