CRYPTOGAMS AND PHENOGAMS 555 
Fic. 381.—Japanese Cycad (Cycas revoluta, Cycad Family, Cycadacee). 
1, seed-bearing plant. 2, macrosporangial leaf or carpel showing the 
naked ovules (macrosporangia) near its base. 3, microsporangial leaf, 
or stamen, showing the numerous microsporangia (anthers) on its lower 
face. (Wossidlo.)—Tree growing about 3 m. tall; fruit densely hairy. 
Native home, Japan; commonly cultivated as ‘‘sago-palm.”’ 
vided with numerous swimming-hairs.- One of these fertilizes the 
ege-cell. After fertilization a seed is formed, an abundance of extra 
food being stored about the single embryo. The sporophyte as it 
develops becomes, as we have seen, singularly like a tree-fern and 
at the same time so closely resembles a Metroxylon as to be called 
by florists a “‘sago-palm.”? While we must of course regard this 
outward resemblance as more or less superficial, it gains significance 
from the presence of much deeper. resemblances which have led 
botanists to regard the Cycad-type as a connecting link between 
the fern and the angiosperm. 
As already shown, the main difference between a gymnosperm 
and an angiosperm is that the latter incases its macrosporangia in 
carpellary leaves. Fertilization is accomplished, however, as before 
by means of a pollen-tube, which, starting from the stigma, has 
simply a longer road to travel before its tip reaches the egg-cell. 
Moisture to enable the microspore to germinate is afforded by a 
stigma, while food for the tubular cell is supplied by the tissues 
along its route. The parts concerned in angiospermic fertilization 
are shown in Fig. 382. When germinating, the pollen-cell produces 
two nuclei, one of which represents the vegetative part of the male 
