128 PBAOTIOAL BOTANY. 



peduncle. Style filiform, its stigma simple. Imperfect sta- 

 mens none. Moss-like, creeping, densely-leafy aquatics. 



Mayaca Michauxii, Schott & Endl. 

 Petals yellow. Flowers imbricated in a head, each 

 in the axil of a coriaceous bract. Style 3-cleft. The 3 fer- 

 tile stamens alternating with 3 plumose filaments. The 2 

 lateral sepals keeled, boat-shaped, the anterior one larger 

 and enfolding the petals in the bud. Xyris. 



90. A whorl of 3 ample (usually broadly ovate) leaves at 

 the summit of the otherwise naked stem, and a terminal 

 showy flower between them. Sepals, petals and styles 3. 

 Stamens 6. Berry 6-angled, 3-celled. Trillimn. 



Leaves not whorled at the summit of the stem. .,..91 



91. Trees and tall shrubs. Flowers polygamous 92 



Herbs or low shrubs. Flowers perfect, or rarely di- 

 oecious 93 



92. Tree thorny. Leaves once or twice abruptly pinnate. 

 Petals 3 (5). Stamens as many, greenish, in small spikes. 

 Fruit a 1- to many-seeded legume. Gleditschia (149). 



Shrub unarmed. Leaves trifoliolate. Flowers green- 

 ish-white, in compound terminal cymes. Sepals, petals and 

 stamens 3 (to 5). Stigmas 2. Fruit a 2-celled, 2-winged 

 samara, winged all around. Ptelea trifoliata, L. 



93. Fruit an achenium. Stamens 6 94 



Fruit a drupe or a capsule 95 



94. Fruit a dry, 3-comered achenium. Perianth of 6 se- 

 pals, the three outer slightly coherent, the 3 inner larger and 

 somewhat colored. Stamens 6. Ovary 1-celled ; styles 3 ; 

 stigmas tufted. Flowers crowded, or whorled in panicled 

 racemes. Rumex (714). 



Fruit of 3 (or 2, rarely only 1) roughish, fleshy ache- 

 nia. Sepals 3. Petals as many, shorter than the sepals. 

 Stamens 6. Ovai-y 3-celled (rather 3 ovaries united at the 

 base ; the style rising from between them.) Stigmas 3. A 

 small herb. Leaves pinnate. Flowers small, solitary, axil- 

 lary. Floerkea proserpinacoides, Willd. 



95. Fruit a capsule. Perianth not scale-like 9V 



Fruit a drupe. Flowers dioeciously polygamous. 



