NATURAL HI8T0BY OF PLANTS. 



Braehyotim 

 Benthaminnvm. 



formed genus, Tibouchina, comprises about two hundred species 

 which grow from the south of Mexico to the south-east of 

 Brazil. 



From the above three subgenera, with some hesitation, we sepa- 

 rate Pterogastra, dichotomous herbs of tropical America, having 4, 

 5-merous flowers with dimorphous anthers ; the connective of the 

 alternipetalous is more prolonged below the anther than that of the 

 others, and may there bear a small appendage wanting in some 

 species. The five angles of the receptacle and the corresponding 

 rib of the sepals are dilated to a verticle dentelate wing, which per- 

 sists to the fruit. 



Aciotis, small herbs of tropical America and the Antilles, has 

 small insignificant flowers, with very slightly- developed calyx. The 

 eight stamens, at first 'incurved, have a short 

 anther, with apical pore, basilar connective, 

 articulated to the summit of the filament, of 

 which it is continuous, with long obconical 

 and truncated style. The ovary is bilocular, 

 and the fruit membranous and indehiscent. 



Not materially differing in organization from 

 the preceding types, Brachyotum (fig. 11) is 

 immediately distinguished by its 4, 5-merous 

 drooping flowers, the petals of which unite in a 

 false campanulate corolla ordinarily surrounded 

 by imbricate bracts forming a calycule. The 

 stamens have incurved filaments and the two 

 cells of the anthers are prolonged downwards 

 in two short and obtuse appendages. Brachyo- 

 tum comprises shrubs of Columbia, Peru, and 

 Bolivia. 



The American plants named Microlicia, by Don, have given their 

 name to a tribe {MicroliciecB), and are distinguished from all the 

 TibouchinecB by the characters of the seed, which is ovoid, oblong, 

 straight or curved, whilst in the Tibouchinece it is more generally 

 cochleate. To these characters we can accord no more than quite a 

 secondary importance. The true Microlicias have a tubular recep- 

 tacle, five sepals of nearly the same length, ten stamens analogous to 

 those of the Tiboiichinece, with anthers at the summit more or less 



Fig. 11. Flo-n-er (f). 



