1958] 



THE BOTANY OF THE GUAYAXA HIGHLAND PART III 



65 



ter I do not favor such a course, because in the first place it would tend to 

 weaken the distinction between the combined genera and Myrcia, and in the 

 second place because such a combination would tend to obscure the very real 

 differences between Calyptranthes and the other genera of the Myrciinae. In 

 most parts of its range, as throughout Mexico, Central America, the West Indies, 

 Andean South America, and probably in southeastern Brazil, Calyptranthes 

 ranks among the most distinctive of genera. As far as I know the troublesome, 

 intermediate species are confined to northern South America east of the Andes, 

 and the flora of this area is relatively so poorly known that any combination of 

 doubtful genera should await much further study. 



The key which follows includes the species of Calyptranthes and Marlierea 

 known to me from the area between the Amazon and Orinoco Rivers, and from 

 Colombian Guayana. Species known only from the Amazon Valley of Brazil or 

 Peru are not included. All the species included in the key are listed in alpha- 

 betical sequence, but complete descriptions are not provided for previously known 

 species unless such descriptions are unavailable elsewhere. 



Relatively few species of these genera are known from the northern Andes 

 and from other areas in northern and western Colombia and northern Venezuela. 

 These species, without any exception that has come to my attention, are either 

 endemic or have their closest relatives in Central America or the West Indies. 

 They constitute a group sufficiently distinct from the species of the Guayana 

 area, and should be studied in detail as soon as enough material becomes available. 



Key to the Species of Calyptranthes and Marlierea 



1. Branehlets 2-winged or 2-carinate, the wing up to 1 mm wide, evident in branchlets of 

 the current season but often wanting in older twigs. 

 2. Distal ends of the wings terminating between the leaf-bases at opposite sides of a 

 node (Calyptranthes type) ; buds 2-3.3 mm long, opening by a ealyptra. 

 3. Leaves acuminate, elliptic-ovate, 5.5-10 cm long, 2.2-3 times as long as wide. 



6. C. lucida. 



3. Leaves rounded or obtuse at the apex, obovate to broadly elliptic or ovate, 

 2.5-5.5 cm long, 1.5-2.5 times as long as wide. 

 4. Leaves obtuse to rounded or subcordate at the base, relatively broad (less 

 than twice as long as wide) ; panicles 3 times compound, 30- to 40-flowered. 



12. C. pullei. 



4. Leaves acute or cuneate at the base, broad or narrow ; panicles reduced, 5- to 

 20-flowered, often spike-like with the flowers sessile along the branchlets. 



11. C. pulchella. 



2. Wings or keels terminating distally in the median lines of the leaf-bases and 

 usually decurrent upon the keeled or angled petioles (Marlierea type) ; buds 2-5 

 mm long, calyptrate or the calyx with 4 (-5) short free tips, the hypanthium split- 

 ting irregularly longitudinally in anthesis. 

 5. Buds about 5 mm long, probably closed and apiculate, covered with appressed 

 golden-brown hairs, the plant generally pubescent ; wings of the branchlets up 

 to 1 mm wide; leaves 15-22 cm long, acuminate; Suriname. 18. M. biptera. 



5. Buds 2-3 mm long ; plants pubescent or glabrous ; branchlets with wings 0.5-3 

 mm high (or merely keeled in 2 species) ; leaves various. 

 6. Buds 3 mm long, appressed-pubescent, closed and apiculate; plants sparsely 

 pubescent with brown sessile hairs; branchlets keeled; leaves 17 cm long, 

 acuminate; Suriname. 33. M. multiglomerata. 



6. Buds 2-3 mm long, glabrous ; free tips of the calyx 0.5 mm long, infolded over 

 the apex until anthesis ; plants glabrous or very sparingly pubescent with 

 bright rufous hairs ; branchlets narrowly winged, or merely keeled in 1 spe- 

 cies; leaves various. 



