354 PLANT STUDIES 
the intra-seminal development. In this condition the em- 
bryo may continue for a very long time, and it is a ques- 
tion whether it is death or suspended animation. Is a 
seed alive ? is not an easy question to answer, for it may 
be kept in a dried-out condition for years, and then when 
placed in suitable conditions awaken and put forth a liv- 
ing plant. 
This " awakening " of the seed is spoken of as its " ger- 
mination," but this must not be confused with the germi- 
nation of a spore, which is real germination. In the case 
of the seed an oospore has germinated and formed an em- 
bryo, which stops growing for a time, and then resumes it. 
This resumption of growth is not germination, but is what 
happens when a seed is said to " germinate." This second 
period of development is known as the extra-seminal, for it 
is inaugurated by the escape of the sporophyte from the 
seed coats (Fig. 315). 
234. The great groups of Gynmosperms. There are at 
least four living groups of Gymnosperms, and two or three 
extinct ones. The groups differ so widely from one an- 
other in habit as to show that Gymnosperms can be very 
much diversified. They are all woody forms, but they may 
be trailing or straggling shrubs, gigantic trees, or high- 
climbing vines ; and their leaves may be needle-like, broad, 
or " fern-like." For our purpose it will be only necessary 
to define the two most prominent groups. 
235. Cycads. Cycads are tropical, fern-like forms, with 
large branched (compound) leaves. The stem is either a 
columnar shaft crowned with a rosette of great branching 
leaves, w r ith the general habit of tree-ferns and palms (Figs. 
16, 316) ; or they are like great tubers, crowned in the 
same way. In ancient times (the Mesozoic) they were very 
abundant, forming a conspicuous feature of the vegeta- 
tion, but now they are represented only by about eighty 
forms scattered through both the oriental and occidental 
tropics. 
