2 SPERMOGONES 
The mycelium in the leaf is strictly localised, forming little 
knotted masses (plectenchyma) just beneath the epidermal 
cells of the affected spot; all the cells of this mycelium are 
uninucleate. Some of these hyphe turn upwards, remaining 
densely crowded and more or less parallel to one another, and 
enclose the flask-shaped cavity, at length converging to a point 
above it and piercing the epidermis at that place. Then the 
upper ends of these hyphe diverge and form a brush-like bundle 
surrounding a narrow canal, or ostiole, which connects the 
cavity with the external air (Fig. 2). Meanwhile other hyphe 
2% 
Fig. 2. P. Caricis. Vertical section of spermo- 
gone, on leaf of Nettle. x 200. 
from the base have grown up within the flask, and made a 
lining to its lower half; these hyphe are exceedingly delicate 
and numerous, and each abstricts from its end, successively, 
large numbers of the spermatia (Fig. 2), accompanied by a 
quantity of sugary mucilaginous matter which binds the 
spermatia into a coherent mass. The mucilage soon swells by 
imbibition of moisture, and the spermatia are forced out of the 
flask, through the ostiole, and form an orange globule between, 
and on the top of, the diverging hairs. Ultimately the mucilage 
dries up, or is washed away by rain, and the spermatia are 
dispersed. 
The spermatia are very small, thin-walled, oblong or roundish 
cells, each containing a single relatively large nucleus, but 
little cytoplasm and no reserve material. When placed in a 
nutritive solution, they are capable of a kind of germination, 
