446 APPENDIX 



GLOSSARY 



Acervulus (acervuli). Open, saucer-shaped, asexual fruiting body. 



See pycnidium. 



^Iciospore (seciospores). Spore borne in an secmm. 

 JEcium (fflcia). Type of fruit-body in rusts. 

 Annulus (annuli). A ring-like portion of a mushroom veil, remaining 



attached to the stem after its rupture and after the expansion of the 



cap, or pileus. 

 Apothecium (apothecia). Open, cup-shaped, sexual fruit-body. 



See perithecium. 



Appressorium (appressoria) . Hold-fast, or organ of attachment de- 

 veloped by certain fungi. 



Ascospore (ascospores). Spore borne in an ascus. See ascus. 

 Ascus (asci). Sexual spore-containing sac, usually developed within 



an apothecium or a perithecium. 

 Bacterium (bacteria). A simple plant of low order lacking chlorophyl, 



or leaf-green. It has no mycelium and each plant is but a single 



cell. Reproduction by fission. Spores sometimes produced. 



See fungus. 



Calyx (calyces). Outer series of leaves of a flower, usually green. 

 Cambium. The growing and formative tissue of a stem or root, found 



between the wood and bark. 



Canker. A definite dead area in the bark of trees or shrubs. 

 Cap. See pileus. 

 Chlamydospore. Thick-walled asexual spore which usually is capabl< 



of resting. 



Chlorophyl. Green coloring-matter in leaves. 

 Cilium (cilia). Thread-like process on bacteria or motile spores which 



aids in motility. 



Conidiophore. A spore-bearing stalk. 

 Conidium (conidia). Asexual spore. . 

 Cortex. Outer bark. 

 Crenulate. Finely notched. 



Cuticle. A continuous waxy film covering the surface of plants. 

 Enphytotic. Said of a plant disease which is habitually and perma- 



nently prevalent in a locality, although not unusuaUy destructive. 



See epiphytotic. , 



Enzyme. A chemical compound capable of assisting or hastening chemi- 

 cal transformation, but without itself entering into the nnal product. 

 Epiphytotic. Said of a plant disease which suddenly appears in a 



locality in an unusuaUy destructive manner. See enphytotic 

 Fungus (fungi). A simple plant of low order lacking chlorophyl, or 



leaf-green. It has mycelium which corresponds to roots. Keprc 



duction by means of spores. See bacterium. 



