210 



MANUAL OF BOTANY 



monoecious, placed on the margin or surface of the frond, or in 

 the axils of leaves. Perianth none. Male Jioiver with 1 or a 

 few stamens, which are often monadelphous. Female Jloiver 

 consisting of a 1-celled ovary, with 1 or more erect ovules. 

 Fruit 1- or more-seeded, membranous or baccate, indehiscent 

 or sometimes dehiscent. E7nbryo straight, cleft, in the axis of 

 fleshy albumen. 



DistribiUion, Numbers, and Properties. — They inhabit cool, 



Fig. 974. 



Fig. 975. 



Fig. 974. A monoecious head of flowers of a species of Duckweed {Lemna 

 minor), consisting of two male fiowers, each of which is composed of a 

 solitary stamen with a quadrilocular antlier ; and one pistillate flower in 



the centre ; the whole surrounded by a spathe. Fig. 975. Vertical 



section of the pistil of the same. 



temperate, and tropical regions. Illustrative Genera : — Lemna, 

 Linn. ; Pistia, Linn. There are above 20 species. Their pro- 

 perties are unimportant. 



Series 6. — Ajyocarj^ce. 



Order 30. TRiUEiDACEiE, the Triuris Order. — Diagnosis. — 

 This is a small order of plants allied to Naiadaceae, but usually 

 to be distinguished by its rudimentary embryo. The flowers 

 are also sometimes perfect. 



Distribution, Numbers, and Properties. — Exclusively found 

 in warm and tropical regions. Illustrative Genera : — Triuris, 

 Miers ; Sciaphila, Blume. There are 8 species. Their pro- 

 perties and uses are unknown. 



Order 31. ALisMACEiE, the Alisma Order. — Character. — 

 Swamp or floating plants. Leaves narrow or with an expanded 



