Knight — 140 — Dictionary 



Spontaneous Generation. — Abiogenesis, q.v. 



Spontaneous Univalent. — A chromosome which has remained 

 unpaired at meiosis owing to the lack of a truly homologous 

 partner, cf. Hereditary Univalent. 



Spore. — A specialized cell usually produced by meiosis and 

 capable of direct production of gametes. 



Spore Mother-cell. — A diploid cell which divides meiotically 

 to produce four haploid spores. 



Sporocyte. — A spore mother-cell. 



Sporogenesis. — Spore formation; the production of spores. 



Sporogony. — Spore formation. 



Sporophyte. — The spore producing individual in the higher 

 plants. The sporophyte is the normal plant (with 2x chromo- 

 somes) ; it gives rise to the gametophyte (with x chromosomes) 

 which produces the gametes. 



Sporophytic Budding. — The production of an embryo from 

 the tissue surrounding the embryo-sac. 



Sporophytic Polyembryony. — Polyembryony brought about 

 by the formation of adventitious embryos by budding from the 

 nucellus or integument. 



Sport. — A mutation; an abrupt deviation from type. 



Spurious Pleiotropism. — See under Genuine Pleiotropism. 



Stamen. — The male organ in the angiosperms, composed of 

 an anther containing the pollen and a filament or stalk; the 

 microsporophyll of the seed plants. 



Staminate. — Of flowers : bearing stamens only. 



Staminode. — An abortive, or imperfectly developed, sterile 

 stamen. 



Staminodia. — Abortive sterile stamens. 



Staminody. — The changing of floral parts into stamens. 



Staminose. — Having stamens which are particularly obvious 

 so that they form a marked feature of the flower. 



Standard. — The large, upright petal at the back of a papilio- 

 naceous flower. 



Standard Deviation. — See Appendix 1. 



Standardised Fertility. — The crude birth rate corrected by 

 a statistical method intended to make allowance for changes in 

 age composition in the population (Carpenter). 



Stasimorphy. — Alteration in form caused by arrested develop- 

 ment. 



Stathmokinesis. — Complete inhibition of anaphase and cell 

 division by treatment with colchicine or some other aberration- 

 inducing substance. 



Staurigamia. — Cross fertilization. 



