388 
STRUCTURE AND LIFE HISTORIES 
gonium, after the first division of the egg, is a suspensor, 
but becomes much longer than in Lycopodium, and 
thrusts the developing embryo deep down among the 
nourishing cells of the gametophyte. By the possession 
of a suspensor the Lycopodiales and Selaginellales are 
distinguished from the Pteridophytes and Catamites. 
The embryo does not cease growth, and pass through a 
resting period, but continues to develop, until its root and 
shoot, with two cotyledons, emerge from the prothallus, 
FIG. 284. Diagram of life-cycle of Selaginella. (Modified from J. H. 
Schaffner.) 
and the young sporophyte gradually becomes established 
as an independent, green plant (Fig. 284). It is only after 
the development of a vigorous leafy shoot, with chloro- 
phyll apparatus, capable of elaborating an abundance of 
food, that the strobilus is organized with its axis and 
green sporophylls. 
