252 GLOSSARY 



Stoma, plu. stomata (a mouth). An opening through the leaf epidermis 



which serves for transpiration. The stomatic apparatus consists of the 



stoma and its guard cells. 

 Stone cell. A hard cell with its walls much thickened by secondary 



deposits, as the grit cells of the pear. 

 Strobilus (a fir cone). A cone-like cluster of sporophylls. 

 Style (a pillar). An elongation of the pistil above the ovary, bearing 



the stigma. 

 Suspensor. In seed plants and club mosses a structure arising from the 



fertilized egg, which pushes the developing embryo deep into the 



tissue of the gametophyte or endosperm. 

 Symbiont. An organism living in a condition of symbiosis. 

 Symbiosis (living together). The condition in which two or more organ- 

 isms are living in intimate physiological relationship. 

 Sympetalous. AVith the petals appearing as if grown together by their 



edges. 

 Synergids (co-workers). Two cells accompanying the egg at the micro- 



pylar end of the embryo sac, the group of three constituting the egg 



apparatus. 

 Synsepalous. With the sepals appearing as if grown together by their 



edges. 



Taxonomy (order, law). The study of classification. Plant taxonomy 



is often called systematic botany. 

 Teleutospores (end spores). The resting spores (chlamydospores) of the 



rusts, producing a promycelium. 

 Testa (a shell). The outer coat of the seed. 

 Tetraspore (four spore). An asexual spore characteristic of the red algae, 



usually produced in groups of four. 

 Thallophytes (thallus plants). The great group composed of the algae 



and fungi. 

 Thallus (a young shoot). A simple vegetative body without differentia- 

 tion into roots, stem, or leaves. 

 Tissue. A definite region of similar cells with the same functions. 

 Trachea, plu. trachece (the windpipe). See Vessel, 

 Tracheid (trachea-like). An elongated cell with closed ends and the walls 



with secondary thickening, as the pitted cells of coniferous wood. 

 Trichogyne. A delicate filamentous extension from the carpogonium, 



specialized to receive the sperms. 

 Tropophyte. A plant which is mesophytic during part of the year and 



xerophytic during the remaining part, as most deciduous trees. 

 Turgor. The inflated or distended condition of a cell which is full of 



liquid. 



Unisexual. Having only male or female reproductive organs. 

 Uredospore (blight spore). A spore of the rusts for rapid multiplication 

 (summer spore). 



