1963] 



BOTANY OF THE GUAYANA HIGHLANDS PART V 



141 



Macairea maroana Wurdack, sp. no v. 



M. pachyphyllae Benth. affinis sed foliis distincte denticulatis floribus 

 maioribus pedicellis longioribus connectivi appendice maiore. 



Ramuli quadrangulares, vetustiores cum cortice in scidulas solutenti, novelli 

 modice cum glandulis flavis sessilibus armati et dense setosi pilis gracilibus 

 stramineis ad 2.5 mm longis eglandulosis. Petioli dense setosi 1-2 cm longi ; 

 lamina 7—11 X 3.5-5 cm elliptica apice acuta basi late acuta vel anguste obtusa 

 breviter (2-4 mm) triplinervata (nervulis marginalibus indistinctis neglectis) 

 nervis primariis lateralibus 3-4 mm ab marginibus distantibus margine irreg- 

 ulariter denticulata dentibus 0.5-1 mm profundis, supra modice strigoso-aspera 

 bullis 1/mm 2 cum seta ca. 1 mm longa armatis, subtus modice (praecipue in 

 nervis nervulisque) ai)presso-setosa superficie cum glandulis flavis 10-15/mm 2 

 armata. Panicula terminalis 4-8 cm longa lataque ; bracteolae usque ad 10 X 5 

 mm valde caducae ; pedicelli 4-9 mm longi cum hypanthio calycis lobisque 

 densiuscule setulosi setulis stramineis glandulosis plerumque ca. 0.5 mm longis. 

 Hypanthium 4.5-5 X 2.5-2.7 mm ; calycis lobi 2.5-3.5 X 1.5 mm anguste trian- 

 gulares apice extus dente glanduloso ca. 0.7 mm longo instructi. Petala 9-13 X 6- 

 10 mm asymmetrice obovata apice rotundata et setulis glanduliferis 1-2 armata. 

 Stamina vix inaequalia, fil a mentis apicem versus glanduloso-puberulis, connectivi 

 appendice rotundato-cordata. Stamina maiora : filamenta 6.5-8 mm ; antherarum 

 thecae 4.7-5.5 mm, connectivo 1.6-3.5 mm prolongato appendice 0.9 X 0.9 mm. 

 Stamina minora : filamenta 4.5-6.5 mm ; antherarum thecae 4.5-5.5 mm, con- 

 nectivo 0.8-1.3 mm prolongato appendice 1.3 X 0.9 mm. Stylus 13 X 0.4-0.5 mm 

 basim versus modice glanduloso-puberulus ; ovarium 4-loculare apice vix elong- 

 atum et sparse vel modice glanduloso-setulosum setulis 0.2-0.4 mm longis ; semina 

 1.2 X 0.7 mm cochleata creberrime foveolata. 



Type. Shrub 1.5-3 m, buds and petals white, anthers yellow, occasional at 

 forest edge just southeast of Maroa, Rio Guaima, Terr. Amazonas, Venezuela, 

 alt. 120-140 m, 9 Oct 1957, Bassett Maguire, John J. Wurdack, & William M. 

 Keith 41772 (holotype US 2342588). Paratypes. Same locality data, Llewelyn 

 Williams 14252, Maguire, Wurdack, & Bunting 36429. 



In Gleason 's synopsis of Macairea, this species would fall in Species-Group II 

 near M. pachyphyUa, M. radula (Bonpl.) DC, and M. viscosa Ducke. M. radula 

 has thicker obtuse leaf blades which are more densely pubescent beneath and the 

 flowers in dense bracteate glomerules; M. pachyphyUa has entire leaf margins, 

 lower leaf surface hairs mostly gland-tipped, smaller flowers (the petals up to 

 7 mm long) on shorter pedicels, and relatively much smaller stamen connective 

 appendages; and M. viscosa has compact conspicuously bracted inflorescence 

 glomerules, more strongly pubescent hypanthium, and longer calyx lobes. M. 

 foveolata Cogn. [cf. Cordeiro & da Silva 311 (NY), from Porto Velho, Terr. 

 Guapore, Brazil] has longer lower leaf surface pubescence, more compact in- 

 florescence glomerules, much longer hypanthial pubescence, and relatively longer 

 calyx lobes. 



Macairea neblinae Wurdack. 



Several large collections made during the 1957-58 Neblina exploration have 

 slightly altered the circumscription of this species. These recent specimens show 

 cauline pubescence often pale and styles often glabrous. These two variables are 

 combined in parts of the collections in all four possible permutations ; no infra- 

 specific distinctions seem warranted. This variability, however, does not alter the 



