1 64 THE FLORA OF THE ALPS 



2. SAGITTARIA, L. 



Flowers unisexual, in whorls; sepals green; petals 

 white ; stamens numerous ; leaves erect, arrow-shaped, 

 thick, very shining 



6 1 . sagitt<zfolia } L., Arrow-head ; ditches ; Switzerland, 

 rare. 



3. BUTOMUS, L. 



Flowers bisexual, in umbels subtended by an involucre ; 

 sepals and petals pink ; stamens 9 ; carpels 6. 



B. umbellatus, L., Flowering Rush; stem 6-12 in., 

 flowers I in. diameter, leaves linear, erect; ponds and 

 streams ; very rare (Bale). 



Order XCIL TYPHACKE. 



Flowers monoecious, in globular or cylindrical spikes 

 or heads; perianth reduced to membranous scales or 

 hairs; ovary I -celled, with usually one pendulous ovule; 

 leaves narrow, with sheathing base ; root-stock a creeping 

 rhizome. Aquatic or marsh plants. 



i. SPARGANIUM, L. 



Heads globose, subtended by leafy bracts ; perianth of 

 3-6 membranous scales; fruit a small i-2-celled drupe. 



5. ramosum, Huds., Bur-Reed; stem erect, branched, 

 leaves triquetrous; ditches, common. S. simplex, Huds.; 

 stem erect, simple ; and 5. minimum, Fr. (including 

 natans, Koch, and affine, Schn.) ; stem and leaves float- 

 ing ; not so common. 





