432 
STRUCTURE AND LIFE HISTORIES 
tance, in the ascending scale, of gametophyte and sporo- 
phyte, and the evidences which point to a possible mode of 
origin of the vegetative body of the sporophyte. A funda- 
mental question, still being debated by botanists, is 
whether, in racial history, the vegetative (sterile) tissue 
appeared first, and the sporogenous (fertile) tissue later, 
'7 
FIG. 321. Diagram of the life-cycle of a pine. (After Schaffner.) 
or whether the fertile tissue appeared first. The question 
may be put as follows: Is the cone (strobilus) the older 
structure in the development of the race, and are the vege- 
tative parts to be regarded as developed from it by pro- 
gressive sterilization? It is better that this question be 
merely stated here, as one of the larger, fundamental 
problems of botany, and that the pleasure of discussing 
it be reserved for the teacher and students together, in 
connection with a later chapter. (Cf., also, p. 379.) 
