448 APPENDIX 
Pileus. Cap of a mushroom. 
Promycelium. A special type of germtube of the rust and smut fungi. 
It forms a basidium with basidiospores or sporidia. 
Protoplasm. Living substance of an organism. 
Pycnidium (pycnidia). Closed, globose or flask-shaped, asexual spore- 
containing body. See acervulus. 
Pycnosclerotium (pycnosclerotia). Sclerotial, body resembling a 
pyecnidium which may become a perithecium. 
Pycnospore. Anasexual spore — a conidium — borne in a pyenidium. 
Rhizomorph. A root-like, branched strand of fungus hyphe. 
Saprophyte. An organism living on dead material. 
Sap-wood. Living wood next to the bark which contains much of the 
sap. 
Sclerotium (sclerotia). A tuber-like vegetative structure of certain 
fungi consisting of a densely woven mass of hyphw which may 
rest for a long period. 
Seta (sete). A bristle, or bristle-like body. 
Sporangium (sporangia). Asexual spore-containing sac. Not in- 
. closed. 
Spore. A cell capable of reproducing a plant like the parent. A 
structure belonging to. the fungi and related plants. Corresponds 
in function to a seed. 
Sporidium (sporidia). Diminutive of spore. Usually applied to spores 
of the rust or smut fungi borne on the promycelium. 
Stoma (stomata). A minute opening in the epidermis of stems, leaves 
and fruits which admits free exchange of gases between the interior 
and exterior. 
Stroma (stromata). A fruiting, or spore-bearing, cushion composed of 
mycelium entirely, or of mycelium and host-tissue. 
Swarm-spore. Motile spore. 
Teliospore. Chlamydospore of a rust fungus which usually rests. 
Produces a promycelium on germination. 
Telium (telia). Sorus in which teliospores are borne. 
Uredinium (uredinia). Sorus in which uredospores are borne. 
Uredospore. Spore of a rust fungus which perpetuates it throughout 
the summer. Produces a germtube on germination. 
Veil. A special membranous envelope in mushrooms, which at first 
eovers the gills. Later remnants of it may be seen on the stalk or 
stipe. 
