24 



KEY AND FLORA 



The flower cluster and the flower of a sedge may be under- 

 stood from an inspection of Fig. 5. 



The species are even more difficult to determine than those 

 of grasses. 



Fig. 5. Inflorescence, flower, and seed, of a sedge 

 (Great Bulrush, Scirpus lacustris) 



A, magnified flower, surrounded by a perianth of hypogynous bristles; B, the 

 seed ; C, section of the seed, showing the small embryo inclosed in the base 

 of the endosperm. (After Lindley) 



6. ARACE.^;. Arum Family 



Perennial herbs, with pungent or acrid juice. Leaves often 

 netted-veined. Small, unisexual or bisexual flowers, clustered 



