54 
THE LEAF 
example of the use of these technical terms, we quote from Lindley the 
descriptions of two leaves : 
Lilac: leaves opposite, exstipulate, roundish-cordate, very acute, 
thin, smooth, rather longer than the linear channelled petiole. 
Garden Strawberry : leaves all radical, ternate, dark-green, some- 
what shining, very coarsely serrated ; with strong parallel oblique veins, 
silky beneath ; leaflets nearly sessile, roundish oblong, entire towards the 
base, shorter than the semi-cylindrical hairy petioles ; stipules mem- 
branous, lanceolate, acuminate, half adnate. 
Reproductive Organs. 
The chief feature in the life-history of a plant is its 
reproduction, and it should be borne in mind that the 
preservation of the individual is of less importance than the 
preservation of the species. It is customary to distinguish 
between vegetative and true methods of reproduction. The 
former is the detachment of portions of the vegetative 
system — specialised for the purpose or not — which may 
grow into new plants without any further reproductive 
phenomena. 4 True ; reproduction, on the other hand, is 
propagation by special cells set apart for the purpose. 
These may be able to form new organisms without any 
sexual process, or they may require, as a preliminary to 
further growth, to fuse together (or portions of them) in 
pairs, male and female. In the first case we speak of 
asexual reproductive cells, or spores , in the second of sexual 
reproductive cells, or gametes , which by their union produce 
a new cell, the zygote , capable of further development into 
a new individual. The spores are contained in little capsules 
or sporangia , seen in typical forms on the back of a fern-leaf, 
or in the pollen-sac of a flower (fig. 6). The leaves on 
which they are borne are termed the sporophylls , and in 
this connection the plant bearing them is called the sporo - 
phyte or asexual plant. The sporangia often form groups 
called sori. 
The spores may be of one kind or of two. In the former 
case (most Filicineae, Equisetum, Lycopodineae, except 
Selaginella and Isoetes) the plant is homo- or isosporous , 
in the latter (all other Pteridophyta and all Spermaphyta) 
heterosporous , with small and numerous microspores in micro- 
sporangia on microsporophylls , and fewer larger mac?'o- or 
