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. 
Fic. 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. ARACEZ. Arum Famity 
Perennial herbs, with pungent or acrid juice. Leaves often 
netted-veined. Small, unisexual or bisexual flowers, clustered 
