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.M. ARUM FAMILY 



Perennial herbs, with pungent or acrid juice. Leaves often 

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



