1963] 



BOTANY OF THE GUAYANA HIGHLANDS PART V 



123 



thy Hum. It is distinguished, however, by the membranous leaves with fewer, 

 more strictly ascending nerves. The species here reported is unusual in that a 

 rim of dense pubescence visible in some degree on both surfaces clothes the 

 margin of the adult leaf. It represents the second species of the genus to be 

 recognized from the sandstone area of the Guayana Highland. 



guttiferae subfam. moronoboideae (American genera) 



It has become currently popular, to some extent on nomenclatural considera- 

 tions, to separate the Hypericaceae from the Guttiferae. Taxonomically this 

 practice seems to be sound, and in these series of papers the hyperics (Hypericum, 

 Vismia, etc.) will be so separated. 



Also, perhaps chiefly on nomenclatural grounds, the residue of the traditional 

 Guttiferae has often been dumped into the Clusiaceae. While I am confident that 

 the familial name Clusiaceae will have a usefulness as representing a natural 

 taxonomic aggregation, I am not at all sure what should go into it. Therefore, 

 until I am better instructed, I shall use the family designation Guttiferae in the 

 more inclusive and historic sense (except for the Hypericaceae) to hold such 

 diversified groups as Clusia and its relatives, Moronobea, Mammea, Rheedia, 

 Calophyllum, etc., until they are to be more satisfactorily placed. 



The Moronoboideae comprises a small obviously natural assemblage of genera 

 chiefly to be found in the Neotropics. But also it shows a wide American, African 

 and Pacific disjunct distribution. The several genera are associated morpholog- 

 ically (within the Guttiferae) most conspicuously by 1) the aggregation of the 

 stamens in five discrete phalanges, 2) the fruit being indehiscent and baccate, 

 and 3) the seed being comparatively large, few in number and without arilli. 

 The small genus Pentadesma is confined to West Africa; the small genus 

 Montrouziera is confined to New Caledonia. Symphonia is represented by 8. 

 globulifera, common to the American tropics and tropical Africa, 8. gabonensis 

 of western equatorial Africa, and, according to Perrier, 16 species in Madagascar, 

 where the genus has apparently become morphologically more diversified. 



In the Neotropics there are five genera, one newly proposed in this paper. 

 None of these genera is large. Symphonia and Platonia, both widespread and 

 plastic, seem to be monotypic. Thysanostemon has two apparently closely re- 

 stricted endemic species. Lorostemon, with three species known at this time, is 

 likewise narrowly endemic. Moronobea, confined to Guayana and the Amazon 

 Basin, has developed at least the seven species that are accounted for here. 



Key to the American Genera of the Moronoboideae 



1. Stamens aggregated in 5 discrete phalanges that alternate with the coral, pink or 

 white petals ; flower buds ovate, conic or oblong. 

 2. Styles distinctly defined, slender, exceeding 1 cm in length, style branches prom- 

 inent, exceeding 3 mm in length; petals ovate or obovate-orbicular, less than 1/2 

 longer than broad, pink or white; flower buds ovoid or conic. 

 3. Stamens numerous, exceeding 50 per phalange, vertically arranged, aggregated 

 in 4-6 series ; ovary not spirally engraved, but with prominent gland-like 

 usually persistent protuberance at base alternating with phalanges. 1. Platonia. 



3. Stamens 3-5 per phalange, uniseriate, often spirally twined about ovary; ovary 

 commonly spirally engraved, basal gland-like protuberance usually not per- 

 sistent af+er anthesis. 2. Moronobea. 

 2. Styles lacking or very short and thick, not distinctly defined, style branches 1 mm 

 or less long; petals linear-oblong, more than twice longer than broad, coraline; 

 flower buds oblong. 



