APOCARPE^ 369 



of Temperate and Tropical regions. Amongst British 

 types are included the Water Plantain, Elisma (by 

 some included in Alisma), Star-fruit, Arrow-head, 

 and Flowering Rush. They appear to be closely 

 related to the next group, the Order Naiadaceae, or 

 Pondweed group. 



Bentham and Hooker make two groups of them, 

 Alismeae, including Alisma, Elisma, Damasonium, all 

 bisexual, Sagittaria unisexual, with green sepals, large 

 fugacious petals, ripe carpels indehiscent, solitary 

 basal ovules, or numerous ovules in the inner angle 

 of the carpel ; Butomese, including Butomus, with 

 the petals and sepals alike, ripe carpels dehiscent, 

 numerous ovules on branching parietal placentas. 



They are aquatic or marsh plants, and all are 

 herbaceous. The rhizomes are perennial. The 

 leaves are radical, and the aerial stems are scapes. 

 The leaves may be erect or floating, or in early stages 

 current leaves of the ribbon type. Small scales 

 occur in the axils of the leaves. There are laticiferous 

 vessels. 



The inflorescence is branched, racemose, then 

 cymose, terminal, umbel-like in the Flowering Rush. 

 The flowers are mainly hermaphrodite or pistillate 

 and staminate, and regular. The perianth is free, 

 six-partite, in whorls^ the inner petaloid and larger, 

 the outer sepaloid. There are six to eight or nine or 

 more stamens which are hypogynous, with free 

 anther-stalks. The anthers are oblong and open 

 outwards. The ovary is superior and consists of 



VOL. III. 24 



