1963] 



BOTANY OF THE GUAYANA HIGHLANDS PART V 



255 



urin<r 24 mm long with lobes 6-9 mm wide ; also, in this collection the calyx-lobes 

 vary on the same inflorescence from 1-7 mm wide. There is also some variability, 

 among the suite of specimens examined in var. orinocense, in the amount and 

 density of pubescence on the lower leaf-surface and in the inflorescence branches. 

 It appears at this time, therefore, better to consider the present newly described 

 taxon in a varietal instead of specific category, allowing for the possibilities of 

 future collections to furnish data for a more definite commitment as to status. 



5. Platycarpum maguirei Steyermark, sp. nov. Fig. 76, 1-J. 



Arbor alta ad 25 m, ramulis novellis glabris ; stipulis caducis ; foliis oppositis 

 coriaceis anguste ellipticis vel elliptico-oblanceolatis apice obtuse acutis vel 

 obtusis basi acutis in petiolum 12-23 mm longum glabrum vel parce adpresso- 

 pilosum cuneatim angustatis 11-25 mm longis 3-7 cm latis, supra manifeste 

 aspero-scabridulis subtus glauco-pallidis costa media nervis lateralibusque parce 

 strigillosis ceterum venulis minutissime strigillosis vel glabrescentibus, nervis 

 lateralibus utroque latere 15-19 adscendentibus in sicco glauco-purpureis costa 

 media paullo elevatis ; petioli una glandula V- vel U-forma 0.6-1 mm lata quoque 

 latere 2-3 mm longo ventraliter inserta ; thyrsis terminalibus 10-27-floris 8-15 

 cm longis 3-8 cm latis 2V2-3-plo longioribus quam latioribus pedunculo 1.5-4 cm 

 longo glabro glauco elevatis, ramulis secundariis ferrugineo-hirsutis superioribus 

 1.5-2 cm longis infimis 3.5-4 cm longis. rhachi in parte inferiore glauca glabra in 

 parte superiore ferrugineo-hirsuta, nodis inferioribus foliis ordinariis vel mag- 

 nitudine aliquantulo redactis suffultis, ramulis superioribus pedicellisque bracte- 

 atis, "bracteis subulatis vel linearibus 3-10 mm longis ferrugineo-hirsutis mox 

 caducis; pedicellis 4-13 mm longis dense ferrugineo-hirsutis; calyce 5-mero 

 10-12.5 mm longo, tubo (hypanthio) campanulato 2.5 mm longo (alto) 6 mm 

 lato einereo-tomentuloso pilis hirsutis ferrugineis vestito, lobis 5 subaequalibus 

 oblongo-lanceolatis subacutis 9-10 mm longis 3-4 mm latis intus sericeis extus 

 tomentulosis pilis ferrugineis strigosis vestitis ; corollis infundibuliformibus albis 

 tubo intus rufotincto notato uno lobo luteo (teste Maguire) 26-27 mm longis (in 

 sicco 20-25 mm) extus dense sericeis, tubo 5 mm longo 6 mm lato intus glabro 

 usque 2-3 mm longo fauce dense barbata superne ampliata 9-11 mm longa supra 

 15-17 mm lata, lobis 5 inaequalibus oblongo-obovatis acutis vel subacutis quatuor 

 8-14 mm longis 6-8 mm latis 1/3-1/2 longitudinem corollae aequantibus intus 

 glabris quinto 13-17 mm longo 6-8 mm lato intus parte media luteo-pubescenti 

 marginibus glabris exceptis; staminibus 5, duobus paullo brevioribus; staminum 

 antheris lineari-oblongis 3.8-4 mm longis 0.8-0.9 mm latis prominenter apiculatis ; 

 filamentis glabris 5-6.5 mm longis ; ovario 2.5 mm alto apice hirsutis pilis erectis 

 dense vestito margine corona instructo ; stylo 7.5 mm longo glabro ; stigmate 2-fido 

 ovato-oblongo obtuso ; capsula ignota. 



Distribution. Extreme southern Venezuela in Territorio Federal Amazonas, 

 where known only from Cerro de la Xeblina. 



VENEZUELA. Amazonas : Cerro Xeblina, slope forest between camp 2 and 

 camp 3; alt. 130-700 m; 5 Jan 1958, B. Maguire, C. K. Maguire, ^Yurdack, d' 

 Keith, Jr. 42597 (holotype NY). 



This species is most closely related to P. clecipiens Woodson & Steyerm. of the 

 Rio Negro-Rio Guainia area, from which it is most readily distinguished by the 

 generally larger corolla with broader, relatively shorter lobes, more spreading 

 rufous pubescence of the upper branches and pedicels of the inflorescence, and 

 relatively narrower inflorescence with shorter lateral branches. 



