HOW TO KNOW THE FRESH-WATER ALGAE 



QUADRATE, four-sided; with 

 a general outline showing 

 four sides 



Quadrigula 50 

 Chodatii 50 



Raaborskia 149 

 bicornis 1 49 



RADIATE, extending out- 

 ward in several planes 

 from a common center; 

 extending in one plane 

 in several directions from 

 a common point. 



Radiofilum 106 

 conjunctivum 1 06 

 flavescens 1 06 



Ragweed 66 



RAPHE, a longitudinal canal 

 within the wall of diatoms 

 belonging to the Pennales, 

 forming a median line on 

 one or both sides of the 

 diatom shell. 



RECTANGULAR, a figure 

 with four right angles. 



RECTILINEAR, arranged in 

 straight rows in two di- 

 rections 



Red Algae, see Rhodophyta 



Red Snow, see Snow 



RENIFORM, kidney - shaped; 

 bean-shaped. Fig. 368 



Figure 368 



REPLICATE, infolded; fold- 

 ed back as in the cross 

 walls of some Spirogyra; 

 not a straight or plane 

 cross wall. Fig. 369 



Figure 369 



RESERVOIR, cavity in the 

 anterior end of flagellated 

 cells from which the or- 

 gans of locomotion arise 



RETICULATE, netted; ar- 

 ranged to form a net- 

 work; with openings. Fig. 

 370 





Figure 370 



Rhabdoderma 185 

 linear e 185 



Rhizochrysis 148, 156 

 limnetica 1 48 



Rhizoclonium 102, 116, 121; 

 also 103 



hieroglyphicum 102 

 Hookeri 1 02 



RHIZOID; RHIZOIDAL, root- 

 like; a downward project- 

 ing root-like branch or 

 cell, usually without regu- 

 larity. 



RHIZOPODIAL, irregularly 

 branched, root-like exten- 

 sions of protoplasm used 

 for locomotion. 



Rhodochytrium 66, also 22 

 spilanthidis 66 



Rhododendron ] 1 5 



Rhodophyta 8, 1 1, 22 110 

 124, 126, 127, 129. 



Ricciocarpus 1 2 

 natons 1 2 



Rivulana 167; also 166 



Rivulariaceae 160 



Rotifer 12 



Roya 73 

 obtuso 73 



SACCATE, like o sac; bal- 

 loon-like cell or colony of 

 cells, or plant body. Fig. 

 371 



Figure 371 



SACCODERM DESMID, false 

 desmids; cells which have 

 plane, unpitted walls all 

 in one piece. See Placo- 

 derm Desmid. 



Sacconema 166 

 rupestre 166 



SARCINA ARRANGEMENT, 

 cells arranged in the form 

 of a cube. 



SCALARIFORM, ladder-like; 

 sexual reproduction by 

 conjugations tubes formed 

 between cells of two fila- 

 ments forming a ladder- 

 like figure. 



Scenedesmus 57, 58; also 

 6, 36 



bijuga var. alternans 57 

 incrassatulus var. mono- 



nae 57 

 opoliensis 57 

 quadricauda 57 



Schizochlamys 45; also 136 

 gelatinosa 45 



Schizogoniaceae; Schizogoni- 

 ales, 92, 98 



Schizogonium 92; also 98 

 crenulatum 92 

 murale 92 



Schizomeris 101 , 110 

 Leibleinii 101 



Schizothrix 165 

 tinctoria 165 



Schroederio 64, 69 

 ancora 64 

 Judayi 64 

 setigera 64 



Scotiella 84; also 14, 33 

 nivalis 84 



SCROBICULATE; SCROBICU- 

 LATION, with saucer-like 

 depressions in a plane sur- 

 face (cell wall), sometimes 

 deep. Fig. 372 



"5o O O O 6o3~o-v 

 o ooo 0o °o 



Figure 372 



Scytonema 174 

 Archangelii 1 74 



Scytonemataceae 161, 175 



Sea Weed 1 1 



Sea Wrack 2 



Selenastrum 53, 65 

 gracile 53 



SEMICELL, a cell-half, as in 

 the Placoderm desmids in 

 which the cell has two 

 parts that are miror im- 

 ages of one another, the 

 two parts often connected 

 by a narrow isthmus. 



SEPTUM, a cross-partition, 

 cross wall or a membrane 

 complete or incomplete 

 through the short diam- 

 eter of a cell, sometimes 

 parallel with the long 

 axis. 



SERRATE, toothed; jagged. 



SETA, a hair, usually aris- 

 ing from within a cell 

 wall; or a hair-like ex- 

 tension formed by taper- 

 ing of a filament of cells 

 to a fine point. Fig. 373 



Figure 373 



SHEATH 

 ly of 

 firm; 

 colony 



a covering, usual- 

 mucilage, soft or 

 the covering of a 

 of cells or an en- 

 velope about one or more 

 filaments of cells. 



208 



