SEED-B EASING PLANTS 43! 
OUTLINE OF LIFE HISTORY OF PINUS 
The pine tree 
(Sporophyte) 
n 
4,4, 
Carpellate cone 
Staminate cone 
(Modified branch) 
(Modified branch) 
14 
44 
Ovuliferous scale 
Stamens 
(Homology obscure) 
(M icrospo rophylls) 
44 
44 
Ovule 
Anthers 
( Megasporangium) 
(M icrosporangia) 
44 
44 
Megaspore-mother-cell 
Microspore-mother-cell 
4, < Reduction 
- 4 
Megaspore 
Microspore 
4 
4 
Embryo-sac 
Pollen-grain 
(Female gametophyte) 
(Male gametophyte) 
4 
4 
Archegonium 
(Antheridial cell) 
4 
4 
Egg 
Sperm 
Oosperm 
44 
Embryo (In a seed) 
(Zygote) 
44 
Embryo-rests 
44 
Germination of seed 
44 
Mature sporophyte (The pine tree) 
385. Comparison with Lower Forms. It will be spe- 
cially instructive, at this point, for the student to make a 
careful comparison of the life history of Pinus with the 
lower forms, such as Cycas, Selaginella, Lycopodium, Equi- 
setum, and a true fern, noting especially the relative impor- 
