454 
STRUCTURE AND LIFE HISTORIES 
"seed-leaves," or cotyledons, and on this basis Ray 
(1628-1705), the noted English botanist, divided the 
class of Angiosperms into two large sub-classes mono- 
FIG. 338. Morphology of typical monocotyledonous plant. A, leaf, 
parallel-veined; B, portion of stem, showing irregular distribution of vas- 
cular bundles; C, ground plan of flower (the parts in 3's); D, top view of 
flower; E, seed, showing monocotyledonous embryo. 
cotyledons and dicotyledons. 1 These two groups are dis- 
tinguished by other characters which are quite con- 
1 Plants like Pinus having more than two cotyledons are polycotyledons . 
