GENERA AND SPECIES. 177 
Naias. 
Stems slender ; leaves very narrow-linear, about 1 in., 
minutely toothed, the sheathing base produced 
into broad stipules 1x : sts ... tenuifolia 
Leaves linear, prominently vogthad’? no stipules... major 
ORDER LEMNACEAE. 
Fronds emitting capillary roots; flower in a fissure of the 
margin, supported by a bract ; anther 2-celled .., .. Lemna 
Fronds minute, without roots; figee ina eu on the upper 
side, no bract, anther 1- celled af, . see .. Wolffia 
Lemna. 
Root-fibres one to each frond. 
Fronds very thin, oblong-lanceolate, the young ones often 
projecting cross-like at both ends.. +0 trisulea 
Fronds broadly ovate, convex Serres th: ahehie 2 fines 
fone. -.., minor 
Root-fibres 2 to 5 to eek ond THiedds thin, oral or wohiones 
rather larger than L. minor ... : sis ae ... Oligorrhiza 
Wolffia. 
Fronds ovate, about 4 line diameter, but very convex 
underneath a iy a Fis see ... Michelii 
ORDER RESTIACEAE, 
1. Minute tufted bisexual plants; leaves radical 
linear ; flowers comprised ordinarily of one 
sepal, one stamen, and one ovary. 
Flowers in a depressed head-like cluster, surrounded by 
spreading transparent bracts ; flor al bracts Oe ys 
1-celled, stigmas 2 or 3 ... aie Trithuria 
Flowers in a single spike on a slender scape; ore rE: eotled, 
opening by a slit. 
Spike supported by several bracts in 2 rows; each 
flower with 1 or 2 hyaline scarious sepals ... .. Aphelia 
Spikes supported by 2 sheathing bracts, each flower 
with 1 to 3 hyaline scarious sepals va om .. Centrolepis 
1. Rush- or sedge-like, mostly unisexual, iaitia’ 
sepals and petals 2 or 3 each ; carpels 3, 
united into a single pistil; fruit 1l- to 3- 
celled ; stamens 3. 
Fruit two- or three-celled ; stigmas 2 or 3. 
Male and female inflorescence in spike-like panicles ; 
bracts loosely imbricate, 2 bracteoles under each 
flower... re Vas =e is Es .. Lepyrodia 
M 
