ON SOUTH-AMEEICAN APOCYNACEJl. 



Macoubea. 



This genus of Aublet, established upon a tall tree in Guiana, has been placed by most 

 botanists in Clusiacece, though Oambassfedes expressed a contrary opinion. Its floral 

 structure is unknown ; but in its other characters it appears to belong to the Apocynacece, 

 because all parts of the plant yield a lactescent juice : its leaves are opposite, with 

 straight divergent nerves arcuately conjoined near the margin, and upon petioles some- 

 what embracing the branch. The fruit, supported upon a short pedicel, is drupaceous, 

 globular, as large as an orange, much resembles that of Oupirana, borne upon the per- 

 sistent calyx ; it is indehiscent, with a rough, brown, thick pericarp, apparently unilo- 

 cular, but only by abortion, as Jussieu observed, for the dissepiment of the ovary is 

 here thrust on one side : it contains several oblong curving seeds, with a hilum in the 

 middle of a ventral furrow ; they are covered by a pulpy covering, which when dry is thick 

 and spongy ; each contains, within albumen, an embryo with two fleshy cotyledons and a 

 small radicle. These characters show a close approach to Amhellania ; and Aublet must 

 have been aware of this affinity, as he figures the two genera in juxtaposition. Only one 

 species is known, and that imperfectly. The following character is partly formed 

 after the examination of Aublet' s typical plant, now in the herbarium of the British 

 Museum. 



1. Macoubea Guianensis, Aubl. PI. Gruian. ii. suppl. p. 18, tab. 378 ; Juss. Gen. p. 257; Juss. Ann. 

 Mus. XX. p. 466 ; Cambass. Mem. Mus. xvi. p. 396 ; DC. Prodr. i. 364 ; Benth. & Hook. Gen. i. 

 169 : arbor lactescens, foliis oppositis, ellipticis, utrinque subacutis,integris, glaberrimis, supra glauco- 

 viridibus, nervis paullo divergentibus arcuatim nesis, reticulatis ; petiolis semiteretibus, in nodum 

 transversim fere junctis, limbo 8plo brevioribus : racemis oppositis, terminalibus, petiolo fere duplo 

 longioribus, crebre plurifloris, floribus brevissime pedicellatis ; sepalis minoribus, rotundatis, convexis, 

 imo gibbosis, et in cupulam brevem coalitis, carnosis, valde imbricatis : pedunculo fructifero brevi ; 

 drupa majuscula, subsphserica subcompressa, vel obsolete trisnlcata, punctis griseis notata, abortu 

 1-loculari ; seminibus plurimis, obtuse oblongis, ad raphen longitudinaliter sulcatis, in came fungosa 

 nidulantibus J embryone intra albumen, oblongo, cotyledonibus 3, plano-convexis, radicula minima 

 nexis. In Guiana : v. pi. s. in herb. Mus. Brit. Cayenne, in sylvis (Aublet) ; fruct. non vidi. 



A tree 40 feet high, with a trunk 18 in. in diameter ; its hard wood, of a greenish yellow 

 colour, emits a fetid odour, all parts of the plant yielding a lactescent juice. The nodes 

 of its branches are 1-2 in. apart ; the leaves are 4 in. long, 2 in. broad, on petioles ^ in. long, 

 conjoined across the node. The fruit is suspended by a pedicel 2 lines long, is about 

 3 in. in diameter, the pericarp being hard and 1 line thick ; the seeds are f in. long, 

 A in. broad, slightly curved and sulcated along one side, by the middle of which they 

 seem to be attached. c 2 



