34 ENGLISH BOTANY. 



In ponds and ditches. Sparingly but widely distributed through- 

 out the kingdom. 



England, Scotland, Ireland. Perennial. Summer. 



Rootstoek rather thick, creeping in the mud, sending up at 

 intervals erect stems wiiicli rise out of tlie water, or if the latter be 

 deep, remain submerged, in which case they swim and have the 

 leaves translucent, without epidermis and without flowers in their 

 axils ; the stems which rise out of the water are stitf, rather thick, 

 8 inches to 2 feet high, Avith close whorls of spreading leaves longer 

 tlian the intcrnodes. Tlowers very small, greenish, in whorls in 

 the axils of the leaves. Anthers reddish. Pruit about the size of 

 a grain of sago, ovoid, smooth, olive-coloured. Plant bright green, 

 glabrous, the submerged leaves paler and broader than those above 

 water. 



Common Mare's-tail, 



French, Fcsse Commune. German, Gemeiner Taunwedel. 



ORDER XXIX.— CUCURBITACEiE. 



Annual or perennial herbs, often rough with hairs or weak 

 prickles, having succulent stems, which usually climb by tendrils 

 which are solitary and from the side of the leaf-stalk. LeaA'es alter- 

 nate, palmatcly-veined and commonly palmately-lobed ; exstipulate 

 unless the tendril be considered as a stipule. Elowers on axillary 

 peduncles, solitary, fasciculate, cymose, paniculate or racemose, 

 monoecious or dioecious, very rarely perfect, commonly yellow or 

 greenish. Calyx-tube short and generally campanulate in the male 

 flowers : sometimes contracted above the ovary and produced beyond 

 it in the female ; limb 5- rarely 6-toothed, valvate, sometimes obso- 

 lete. Corolla of 5 petals, inserted on the limb of the calyx, distinct 

 or commonly more or less united with each other and adhering to 

 the calyx, usually conspicuously veined. Stamens 5, conflncd to the 

 male flowers, usually united in 3 sets of 2, 2, and 1 sej)arate, rarely 

 free ; filaments short and thick, sometimes all more or less united 

 at the base ; anthers generally long and variously folded or flexuous, 

 adnate, cxtrorse, generally 2-celled. Ovary confined to the female 

 flowers, inferior, 3- to -S-celled, more rarely 1-celled, the edges of 

 the carpels inflected until they reach nearly to the centre, when 

 they still continue curving inwards until the placentae are brought 



