Sporangium : a cell in which spores are produced ( often zoospores ) . 

 Spore: a one-celled, asexual reproductive element, with or without a wall. 

 Statolith: granule functioning as a balancing organ relating the cell to gravity. 

 Statospore: spore smaller than the parent cell, formed within the shell (frus- 



tule ) of diatoms. 

 Stauros: a stake; a stout, pole-like extension; an external central nodule in 



some diatoms. 

 Stellate: star-shaped. 

 Stephanokontae: plants which have motile reproductive cells furnished with 



a crown of flagella. 

 Stigma: the red granule or group of granules making up the hght-sensitive 



spot in zoospores and flagellates. 

 Stipe: a stalk. 

 Stratum: a layer. 



Striae: delicate, long, narrow markings. 

 Stroma: supporting tissue or mass of cells serving as a base for upright branches 



or other organs. 

 Sub — : shghtly or nearly, as subglobular; vmder; beneath. 

 Subbiconic: nearly or somewhat double cone-shaped. 

 Subhexagonal: somewhat six-sided. 



Subparenchymatous: somewhat cushion-hke; approaching the mound-like ar- 

 rangement of cells, in two or more layers. 

 Subpijriform: somewhat pear-shaped. 



Suffultory cell: a cell resulting from the division of a vegetative cell, the 

 upper segment of which forms an oogonium, the lower segment a some- 

 what enlarged suffultory cell. 

 Sulcus: the longitudinal furrow in dinoflagellates. 



Superior pore: a pore in the upper part of an oogonium ( Oedogoniaceae ) . 

 Supramedian: slightly above the median plane. 



Suture: furrow or groove; trough between plates in wall of dinoflagellates. 

 Symbionts: two dissimilar organisms living together in close association. 

 Symbiotic: a condition in which two different organisms Hve together. 

 Systole: contraction period in action of pulsating vacuoles. 

 Tangential: section or cut made at right angles to the radius. 

 Tegument: a sheath or envelope. 

 Terebriform: twisted or twist-hooked, augur-shaped. 

 Test: an external shell inclosing the protoplast (e.g. Trachelomonas) . 

 Tetrad: four cells formed by two divisions from a spore mother cell. 

 Tetrasporine tendency: evolutionary trend in green algae from a motile uni- 

 cell through a palmelloid condition to a Tetraspora-Mke expression, and 

 then to a filamentous form. 

 Thalloid: like a plant body which has no roots, stems, or leaves. 

 Thallus: a plant body in which there is little or no differentiation of cells to 



form tissues. 

 Tie cells: cells in the thallus of some red algae which connect peripheral cells 



to a central axis. 

 Tomentose: covered with numerous fine hairs. 



Torulose: twisted; flexuous, as in irregularly spiralled species of Anabaena. 

 Transverse: across the short diameter. 

 Transverse furrow: groove extending (at least partly) around the dinoflagel- 



late cell in the midregion. 

 Trapezoid: a plane figure which has two parallel sides. 

 Trichites: silicious spicules; a tuft of bristles. 



[608] 



