HOW TO KNOW THE FRESH-WATER ALGAE 



TRAPEZIFORM; TRAPEZOID, 

 a figure which has two 

 parallel sides; shaped 

 somewhat like a trape- 

 zoid. Fig. 376 



Figure 376 



Trebouxia 80 

 Cladoniae 80 



Trentepohlia 109, 116, 119; 

 also 10, 13 

 aurea 1 09 

 lolithus 109 



Treubaria 87 

 crassispina 87 



Tribonema 131; also 132 

 bombycinum 1 3 1 

 bombicinum var. tenue 



131 

 utriculosum 131 



TRICHOCYST, organelle 

 which is capable of throw- 

 ing out stinging fibrils of 

 mucilage. (See Gonyosto- 

 mum, Fig. 4.) 



Trichodesmium 162, 163 

 erythraceum 1 62 

 lacustris 1 62 



TRICHOGYNE, a slender ex- 

 tended neck on the fe- 

 male sex organ (carpo- 

 gonium) of the Rhodophy- 

 ta. 



TRICHOME, a thread; the 

 series of cells in the Cy- 

 anophyta exclusive of a 

 sheath which may be pres- 

 ent; a fine hair-like ex- 

 tension. 



Triploceras 70 

 gracile 70 



Trochiscia 80 

 granulata 80 

 obtusa 80 

 reticularis 80 



TRUE BRANCH, a branch 

 formed by means of later- 

 al division of cells in the 

 main filament of a plant. 



TRUNCATE, cut off abruptly 

 at the tip; flat at the 

 end as opposed to being 

 rounded or pointed. Fig. 

 377 



Figure 377 



TUBERCLE, a button - like 

 knob or protuberance. 



TUBULAR; TUBULAR T HAL- 

 LUS, a thread-like growth 

 without cross walls; a 

 plant body in the form 

 of a tube. 



TUMID, swollen or convex 

 on the sides. Fig. 378 



Figure 378 



Tuomeya 1 26 

 fluviatilis 1 26 



Turtle 13, 19 



TYCHOPLANKTON, the 

 plankton of waters near 

 shore; organisms floating 

 and entangled among 

 weeds and in algal mats, 

 not in the open water of 

 a lake or stream 



U 



also 101 



Ulothrix 107, 1 08; 



aequalis 1 07 



cylindricum 1 07 



zonata 1 07 

 Ulotrichales 53 

 Ulvella 1 1 5 



involens 1 1 5 

 UNDULATE, regularly 

 UNILATERAL, on one 

 UNISERIATE, 



in a single 



tiseriate. 

 Urococcus 82 



insignis 82 

 Uroglenopsis 



americana 

 Uronema 1 08 



elongatum 1 08 

 UTRICLE, a sac-like or tub- 

 ular sheath, usually a firm 



mucilaginous covering. Fig. 



379 



cells 

 row. 



155 

 155 



wavy. 



side, 

 arranged 

 See Mul- 



Figure 379 

 Utricularia 15, 51 



VALVE, one of two parts 

 of a diatom cell wall; 

 valve view, when the cell 

 is seen from the top or 

 bottom; girdle view, when 

 the cell is seen from the 

 side which thus shows the 

 overlapping of the two 

 valves. 



Vaucheria 1 24 

 geminata 1 24 

 sessilis 1 24 



VEGETATIVE, referring to a 

 non - reproductive stage, 

 activity, or cell, as op- 

 posed to activities and 

 stages involved in repro- 

 duction, especially sexual 

 reproduction. 



VENTRAL, the under or low- 

 er side or surface of an 

 organism or cell. 



VERMIFORM, long, narrow 

 and crooked in shape, 

 worm-shaped. 



VERRUCA, a warty projec- 

 tion; a protrusion which 

 bears knobs or spines. 

 Fig. 380. 



y^^ 



Figure 380 



VERRUCOSE, roughened; 

 with irregular thickenings 

 on the surface. Fig. 381 



VESICLE, a sac or balloon- 

 like cell or thallus. 

 Volvocaceae 26 

 Volvocales 27, 36, 84 

 Volvox 28; also 29, 30 155 

 tertius 28 



W 



WATER BLOOM, a profuse 

 growth of planktonic al- 

 gae which cloud or color 

 the water, often forming 

 floating scums. 



Water Net (Hydrodictyon) 

 54 



Westella 60 

 botryoides 60 



WHORL, several 

 branches or leaves 

 ing at one level 

 around an axis. 



Wislouchiella 32 

 planctonica 32 



VVollea 171 

 saccata 1 7 1 



parts, 

 aris- 

 from 



210 



