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MEMOIRS OF THE XKW FORK BOTANICAL GARDEN 



[VOL. 10 



4b. Platycarpum orinocense var. grandiflorum Steyermarkj var. now 



Arbor 2-10 m, ramis novellis ferrugineo-hirsutis ; foliis oppositis coriaceis 

 obovato-oblongis vel obovatis apice rotundatis basi in petiolum 11-15 mm Ionium 

 brunneo-hirsutum cuneatim angustatis 14-23 cm longis 8-11 cm latis supra 

 aspero-hirsutulis subtus molliter villosis pilis 2-3 mm fulvis vestitis, nervis 

 lateralibus utroque latere 14-18 ; petioli una glandula subreniformi ventraliter 

 inserta ; thyrsis terminalibus 15 cm longis 15 cm latis, pedunculo 3.5-6 cm longo 

 ferrugineo-hirsuto elevato, rhaehi ramulis secundariisque ferrugineo-hirsutis vel 

 tomentosis; pedicellis 5-12 mm longis ferrugineo-hirsutis vel tomentosis; calyce 

 4-5-mero 11-13.5 mm longo, tubo (hypanthio) 1.5 mm alto 4 mm lato ferrugineo- 

 hirsutulo, lobis 4-5 oblongo-lanceolatis subacutis 10-12 mm longis 4.5-6 mm latis 

 extus tomentoso-hirsutulis pilis fulvis instructis intus dense sericeo-strigosis pilis 

 pallidioribus brunneis vestitis; corollis campanulato-infundibuliformibus albis 

 basilariter rufotinctis maculatisque (teste Cowan <& Wurdack) 25 mm longis, 

 tubo 4 mm longo intus glabro usque 2.5-3 mm longo fauce dense barbata superne 

 ampliata 13-14 mm longa, lobis 5 inaequalibus, uno lobo vel duobus lobis albis 

 parte media pilis luteis vestita basilariter rufotinctis maculatisque instructis 

 (teste Cowan d' Wurdack), oblongo-ovatis apice abruptis acutis interdum ro- 

 tundatis 10-11 mm longis 8-10 mm latis uno lobo vel interdum duobus lobis intus 

 luteo -villosis ceteris glabris ; filamento 7.5-9 mm longo ; capsula ignota. 



Distribution. Known only from Serrania Paru, Territorio Federal Amazonas, 

 Venezuela. 



VENEZUELA. Amazonas: frequent in savanna at west base of Cerro Paru, 

 Serrania Paru, alt. 200 m ; tree 2-10 m ; 3-4 petals white with red streaks and 

 blotches basally; 1-2 petals white with red streaks and blotches basally but 

 irregular with central yellow hairs; 15 Feb 1951, Cowan d: Wurdack 31473 

 (holotypeNY). 



This variation of P. orinocense, known thus far only from the Cerro Paru, 

 differs from the more widespread P. orinocense var. orinocense in the larger calyx 

 and corolla, longer filaments, ferruginous-hirsutulous peduncle and branches of 

 inflorescence, more conspicuously pubescent lower surface of the leaf -blades with 

 buff-tawny hairs 2-3 mm long instead of whitish and less conspicuous hairs 

 0.5-1.5 mm long of var. orinocense, and more densely pubescent upper leaf 

 surfaces with hairs 0.2-2 mm long instead of all short-pustulate based hairs 

 0.1-0.5 mm long of var. orinocense. Most of the corolla-lobes in var. grandiflorum 

 are abruptly acute as contrasted with rounded in var. orinocense, but the fifth 

 lobe in Var. grandiflorum may be rounded, and there is some transition in this 

 character, thus breaking down the differences that might otherwise exist between 

 the two varieties. Rarely two lobes, instead of the usual one, of a corolla are 

 encountered having the inner surface densely yellow-bearded down the central 

 portion continuing to the base of the limb. If this were of constant occurrence, 

 it would constitute a specific character, but examination of the holotype col- 

 lections shows that the bearded condition may occur on one or two lobes, and 

 is not constant. 



While the differences separating var. grandiflorum from var. orinocense 

 appear to be of specific character at first, variation noted in some collections of 

 var. orinocense in corolla size break down some of the apparent differences. 

 Thus, in Maguire, Wurdack, & Bunting 36063, for example, taken near the type 

 locality of Puerto Ayacucho (near rapids of Ature), some corollas are small, 

 measuring 17-19 mm long with corolla-lobes 5.5-6 mm wide, others are large, meas- 



