Explanation of Terms. 203 



KXi*i.A.\.vri().\ OF ^ri':wMs. 



Abstrktion. — The formation of a spore by pinching off the eml of a spore-forming hypha. 

 Aecidiosporc. — A spore formed in an aecidiuni, being produced in chains from the hymeniiun 



lining tiie internal surface. 

 Aecidium. — The usually cup-shaped envelope witiiin which aecidiospores are jiroduceil. 

 Alien. — An introduced plant which has become naturalized. 

 Amphimixis. — The intermingling of the properties of the two sex-cells in the process of 



fertilisation, when they are clearly distinct. 

 Anastomosis. — The union of hyphae by numerous cross-connexions, forming an irregular 



network. 

 Anti-toxin. — A secretion wliicli neutralizes or counteracts the effects of a toxin or 



poi.sonous secretion. 

 Ascomycetes. — 'A group of fungi in which tiie sijores are produced by free-cell fornu^tiou 



in a mother cell or ascus. 

 Asciis. — The spore mother-cell, wliich is usually the swollen end of a hypha. 

 Autobasidium. — An undivided basidium, consisting of a single large cell. 

 Basidiomycetes. — A group of fungi producing spores on basidia. 

 Basidium. — A terminal tubular cell, bearing at its apex a definite number of spores or 



conidia, usually four ; or divided transversely, and each cell giving rise to a 



reproductive body. 

 i?f/.sipetaL— Applied to conidia or spores when the youngest of a chain are produced at 



the base. 

 Bunt. — A common name applied to Stinking Smut of wheat. 

 Cereal. — Any of the grasses whose grains serve as food. 

 Chemotaxis or Chemotropism. — A form of sensitiveness which certain organisms possess 



towards particular chemical substances. 

 Chlamydosporc. — -A thick-walled resting-spore. 

 CldorophyU, — The gi-een colouring matter of plants, which enaljles the chlorophjdl 



grains to utilize inorganic food. 

 Conidium. — A reproductive cell asexually produced and arising by a process of budding. 

 Co)iju(/ation.— The fusion of sexual elements, the two uniting elements or gametes being 



similar. 

 Contagion. — The transmission of disease by direct contact of the part afifected with the 



Dominant. — Applied to such characters arising in the crossing of two individuals as prevail 



and assert themselves over contrasted characters A\hich are kept in the back- 

 ground. 

 Echinulate. — Covered with short spines. 

 Endos pore. —The innermost coat of a spore. 

 Exospore. — The outer covering of a spore 

 Fertilisation. — The union of two ucnu-iclls derived from male and female organisms 



respectively and becoming |ili\ ^inlogically one. 

 Fungi. — Plants destitute of chl<Mci|ili\ II. and without the systems of tissues characteristic 



of higher plants, but may be unicellular or composed of more or less compacted 



strands of cells or hyphae. 

 Fungicide. — Any substance which acts injvu'iously to fungi or destroys them completely. 

 Gall. — A monstrous growtli or morbid enlargement of the cells of a ])lant. due to 



parasitic agency. 

 Gametes. — -CTcrra-cells derived from nuilc or female organisms, that from the male being 



known as spermatozoon or sperm cell, and that from the female as ovum or egg-cell. 

 Gamefophyte. — The stage in the life-cycle of a plant which bears the sexual organs. 

 Germinal tube. — A tubidar process from a spore developing into a promyceliuni. 

 Germ-tube. — A tubular process from a spore or conidium developing into a Iiypha. and 



ultimately into a mycelium. 

 Haustorium. — A short lateral brancli of a liypha. penetrating a cell of tlie liost-plant. and 



acting as a sucker as well as an organ of attachment. 

 Hemibasidia. — A term applied by Brefeld to the promycelia of tli(> Suuits. as they siu)w 



their primitive nature by being divideil and bearing a variable number of conidia. 

 Heredity. — ■" The genetic relation between successive generations," or " The transference 



of similar ciiaracters from one generation of organisms to another, a process effected 



by means of tiie germ-cells or gametes." 

 Host or Host-plant. — A plant whicii nourishes a parasite. 

 Hyaline. — Colourless or translucent. 

 Hymenium. — A spore-bearing layer of hyphae. 

 Hypha. — A tubular tlu'cad-like structure, collectively constituting the vegetative body 



or mycelium of the fungus. 



