I. HYDEOCHARIDE^}. 



755 



Hydroehari*. 

 Fruit, entire and dehiscent (nat. size). 



Hydrocharis. 

 Stigma tic branch, 

 opposite to sepals. 



Hydrocharis. 

 Stigmatic branch, 

 opposite to petals. 



Hydrocharis. 



Young fruit 



(mag.). 



Hydrocharis. 



Transverse section of ovary 

 (mag.). 



Hydrocharis. 



Eudimentary ovary in a 



<? flower. 



Hydrocharis. 

 Ovule (mag.). 



Hydrocharis, 



Vertical section of see 



(mag.). 



Hydrocharis, 

 Embryo seen in front (mag.). 



Hydrocharis Aforsus-rmii?. 

 Embryos seen in profile ia various stages of germination (mag.). 



FLOWERS usually diclinous, enclosed in a membranous spathe. PERIANTH 6-merous, 

 2-seriate (calyx and corolla). STAMENS 3-6-9-12, inserted at the base of the perianth, 

 several often sterile. OVARY inferior, 1- or more-celled ; OVULES several in each cell, 

 ascending or orthotropous, placentation parietal. FRUIT a utricle or berry. SEEDS 

 exalbuminous. Aquatic PLANTS. LEAVES usually radical. 



Aquatic HERBS, usually perennial, submerged or floating, stoloniferous, some- 

 times gemmiparous at the axils (Hydrocharis). ROOTSTOCK short and creeping, or 

 elongated, jointed and knotted, cylindric. LEAVES usually all radical, rarely cauline, 

 opposite or whorled (Udora, Anacharis, &c.), floating 'or submerged, sometimes 

 emerged, petiolate ; blade entire, vernation convolute ; petiole sometimes sheathing 

 at the base, often reduced to a phyllode by the arrest of the blade ; nerves longitu- 

 dinal, margins denticulate (Vallisneria, Blyxa). FLOWERS dioecious, rarely $ (Udora, 

 Ottelia) ; buds enclosed in a membranous or herbaceous spathe, which is sessile or 



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