ON THE MELASTOMACEiE. 297 
Obs. Genus ab singulari integumento calycis bene discri- 
minatum est. Semina nondum vidi, quod capsulam esse im- 
maturam, ideoque genus solum habitu in hac sectione ordi- 
nandum. Nomen a ^tTrXo^y duplex, et cgyu^ tectum, ab ealyp- 
tra duplici calycis. 
Rhexia, Li7in,, E. Brown. 
Hhexi.e sp. Auctor. 
Cdly^ tubuiosuSj basi demum amplians, ventricosus^ 
apice in coUo angustatus : Umbo urceolato, 4-iido5 persis- 
tente* Petala 4, in ore calycis insidentia, late obovata. 
Stamina 8 : filamenta longa, erecta, compressa, ^qualia^ 
in ore calycis intra petala inserta, inarticulata : antlieroe 
lineares, declinatae, obtusa? absque rostro, aequales, apice 
foramine hiantes, infra dorso nec basi filamenta insidentes, 
basi non constrictae. Ovarium in ventro calycis liberum. 
Stylus rectus, teres staminibus brevior. Stigma parvumy 
subcapitatum, tenuissime barbatum. Capsula globosa, in 
ventro calycis inclusa, libera, 4-locularis, 4-valvis : valvis 
rima oblonga singulis in medio loculi liiantibus. Placentce 
4, lunatse, pedicello brevi piano ad axem centralem ad- 
nato suffultas, compressae, valde scrobiculatae, in medio 
loculi centraliae, seminibus creberrime et imbricatim tectse. 
Semina oo, reniformia, punctata, umbilico amplo concavo 
terminata: testa simplex crassiuscula, Crustacea, fragilis: 
albumen nullum. Embryo teres, curvatus, lacteus : cotyl. 
breves semicylindric^ : radicula curvata, centripeta, coty- 
ledonibus duplo longior. 
Herbag loaves, humiles {Boreali-Americance), perennes 
rarius annuce. Caules erecti, tetragoni, glabri. Folia 
opposita, sessilia, integerrimaj Unearia., lanceolata v, ovafa. 
