VASCULAR PLANTS OF THE YANGTZE VALLEY 



Heads unisexual (monoecious), glabrous, without 



involucres 171. Sparganiaceae 



Heads androgynous, pubescent, with involucres. ..183. Eriocaulaceae 

 Fls. in cymes or fascicles: rush-like or grass-like 



plants: fr. a capsule 186. Juncaceae 



7b. Fls. in spikelets: grass-like or rush-like plants. 



Stems cylindrical, usually with hollow internodes: lvs. 

 2-ranked; the sheaths split: anthers versatile: fr. 



a caryopsis 178. Gramineae 



Stems triangular (occasionally cylindric) and solid: lvs. 

 3-ranked; the sheaths closed: anthers basifixed: fr. 



an achene 179. Cyperaceae 



6b. Perianth present; at least the inner segments petaloid. 

 9a. Apocarpous; carpels several, distinct and separate from 

 the beginning. 



Fr. a cluster of achenes: lvs. basal and sheathing 175. Alismaceae 



Fr. of several many-seeded follicles: fls. 



perfect: lvs. rush-like 176. Butomaceae 



9b. Syncarpous, at least when young. 



Carpels 3-6, at first united into a superior ovary, be- 

 coming distinct at maturity: fls. perfect, in racemes 



or spikes: lvs. terete 174. Juncaginaceae 



Carpels 1-3, not separating at maturity. 



Ovary inferior: stamens all alike: fls. unisexual or 



polygamous: lvs. simple and entire 177. Hydrocharitaceae 



Ovary superior: stamens often unequal, fls. perfect: 

 lvs. petioled and with thick blades or long and 



grass-like 185. Pontederiaceae 



lb. Terrestrial plants, often growing in moist places. 

 10a. Trees and shrubs. 



Stems hollow, jointed: lvs. linear to oblong, not palm-like: fr. 



a caryopsis Bambuseae 



Stems solid. 



Trees with palm-like lvs. : f r. drupaceous 180. Palmae 



Shrubs (often vines) with prickly stems: fr. a berry Smilax 



10b. Herbs. 

 11a. Fls. in spikelets: grass-like plants with jointed stems. 



Stems cylindrical, usually hollow: lvs. 2-ranked; the sheath 



split: anthers versatile: fr. a caryopsis 178. Gramineae 



Stems mostly triangular and solid: lvs. 3-ranked; the sheaths 



closed: anthers basifixed: fr. an achene 179. Cyperaceae 



lib. Fls. not in spikelets. 



12a. Infl. a spadix, enclosed by a spathe 181. Araceae 



12b. Infl. not a spadix. 

 13a. Perianth of green, brown or purplish scales: grass-like 



plants 186. Juncaceae 



13b. Perianth, or one series of the segments, petaloid, some- 

 times greenish. 

 14a. Ovary superior. 

 15a. Calyx and corolla clearly differentiated. 



Lvs. alternate : seeds few 184. Cemmelinaceae 



Lvs. verticillate: seeds several Paris 



15b. Perianth segments all petaloid. 



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