154 THE FLOWERING PLANT. 
kinds, z.e., small microspores contained in microsporangia, and 
much larger macrospores contained in macrosporangia. The 
leaves which bear microsporangia are male sporophylis, and those 
which bear macrosporangia female sporophylls. The odphyte is 
much more reduced than in the fern and is represented by a 
minute male prothallus developed within the microspore, and 
a rather larger female prothallus developed within the macro- 
spore. The former is very little more than a big antheridium 
which produces numerous antherozoids something like those of 
a moss, while a small number of archegonia are developed on 
the female prothallus, which, when mature, projects a little 
from the ruptured macrospore. The egg-cell of one archegonium 
is fertilized by the fusion therewith of an antherozoid, and grows 
into a sporophyte. 
In a flowering plant the odphyte it still more reduced. The 
pollen-grain is a microspore and its contents are to be regarded 
as an excessively reduced male prothallus, while the embryo-sac 
is a macrospore, and when fully matured its contents are equiva- 
lent to a minute female prothallus which never becomes inde- 
pendent of the sporophyte. The following table explains the 
relation between the life-history of a flowering plant (angio- 
sperm) and that of selaginella :— 
SELAGINELLA. ANGIOSPERM. 
SPOROPHYTE = “the plant.” 
I. male sporophlly = stamen. 
microsporangium . = pollen sac. 
microspore . = pollen grain, 
2. female sporophyll = carpel. 
macrosporangium. = ovule. 
= macrospore = embryo-sac. 
OOPHYTE. 
I. male prothallus = contents of pollen grain (p. 98). 
antheridium . = pollen tube. 
antherozoid = part of pollen tube contents (p. 114). 
2. female prothallus. = contents of embryo-sac (p. 109). 
archegonium = co-operating cells and egg-cell represent 
three reduced archegonia. 
ege-cell = egg-cell. 
From the foregoing it will be understood that a seed is equi- 
valent to a developed macrosporangium containing an embryo 
sporophyte in a dormant condition. 
