290 SCHOMBURGK’S GUIANA PLANTS. 
DC., should form of itself a section which I have called 
Echinogonum, on account of the remarkable calyx; thata 
fourth group is that referred by De Candolle to Osbeckia, — 
under the sectional name Pterolepis: that Ladanopsis (DC.), 
is a fifth, and that Monochetum, (DC.), Trifurcarium, (DC.), 
Centradenia, (Don), and Heeria, (Schlecht.), are either dis- — 
tinct genera, or so many additional sections of Chetogastra. - 
The first two of the above sections are generally pentame- — 
ous, with a few tetramerous or variable species; the third is 
pentamerous; the fourth is as often tetramerous as penta 
merous; the fifth usually ánd the remainder always tetra- 
merous. The number of cells of the capsule, in all the — 
species I have examined, corresponds with that of the se A 
of the flower. nd 
. Macairea is readily known by the glandular sete of the a 
calyx and ovary, and the stipitate glands of the longer ! fila- 
ments. They are all shrubs, with the upper side of the o 
leaves closely covered with tubercles or pustules, usually e 
terminating in rigid erect setze, so that they can B 
be described as glabrous, as in De Candolle's generic char- i 4 
acter, though they certainly have not on the upper side ud y 
ferruginous down of the under one. - ae 
313, Tibouchina aspera, Aubl.—DC. Prod. III. p. I E 
Savannahs, British Guiana, Schomburgk, n. 252. uA * 
314. Chatogastra (Diotanthera) gracilis, DC. .Prod. p E. 
p. 133.— Marshy savannahs, Mount Roraima. ! A 
~-Chamisso is probably right in uniting this plant, the C. E 
repanda, (Mart.), and several others under one name. —  — 
. 815. C. (Diotanthera) hypericoidés, DC. Prod. III p.189 4 
—C. lychnitoides, DC. 1. c. —British Guiana. Schomburg — 
n. 133 and 719.—4A common plant in North Brazil- Gard- a 
ner’s n. 377 appears to be C. Martiana, DC. d 
_ 816. C. (Echinogonum) divaricata, DC. Prod. Mp L $ 
ritish Guiana. Schomburgk, n. 721. = = 
C. (Pterolepis) glomerata, Mart.— Osbeckia glomer ^ 
HI. p. 141.— Arthrostemma iem MH 
mp p. 454. Flores sempe pentameri.— 9r" 
