HOW TO KNOW THE SEAWEEDS 



Pikea (No. 92) 173 

 californica 173 

 pinnata 173 



PINNATE: with the branches 

 in a rank on either side 

 of the axis. 



PLASMOLYSIS: the contrac- 

 tion and shrinking of the 

 cytoplasm of a cell (and 

 sometimes the collapse of 

 the cell wall as well) as 

 a result of loss of water 

 through exosmosis. 



Pleonosporium (No. 143) 86 

 borreri 86 

 dosyo/des 86 



Pleurophycus (No. 61) 127 

 gardneri 1 27 



Plocamium (No. 118) 172 

 pad fi cum 17? 

 violaceum 1 72 



Plumana (No. 146) 169 

 californica 1 69 

 densa 1 69 

 filicina 169 

 hypnoides 1 69 

 pectinata 1 69 

 sericea 169 



PNEUMATOCYST: an air 

 bladder or vesicle. 



Polyneura (No. 151) 128 

 latissima 1 28 



Polysiphonia (No. 165) 53 

 67 



POLYSIPHONOUS: provided 

 with transverse tiers of 

 parallel, vertically elongat- 

 ed cells of approximately 

 equal length, Fig. 254. 



sions produce more than 

 four spores (polyspores). 

 Fig. 255. 



\OD00' 

 lOQDCD 



inmrn 



Figure 254 



POLYSPORANGIUM: on asex- 

 ual reproductive structure 

 in the Red Algae (Flori- 

 deae) in which the divi- 



Porphyra (No. 80) 70 



perforata 70 

 Postelsia (No. 67) 156 



palmaeformis 1 56 

 PROLIFEROUS: producing 



outgrowths similar to the 



original. 

 Pterochondria (No. 167) 68 



wood a 68 

 Pterocladia (No. 89) 175 



caloglossoides 175 



pyramidale 175 



I 67 

 139 



Pterosiphonia (No. 166 



dendroidea 67 

 Pterygophora (No. 71) 



californica 1 39 

 Punctaria (No. 50) 149 



lati folia 149 



plantaginea 149 

 Pylaiella (No. 29) 81 



litoralis 81 



RADIALLY SYMMETRICAL: 

 having similar parts regu- 

 larly arranged about o 

 central axis. 



Ralfsia (No. 30) 89 



RECEPTACLE: in the Fucales 

 a fertile branch or branch 

 tip bearing reproductive 

 conceptacles. 



RETICULATE: 

 form. 



Rhipocephalus 

 oblongus 1 23 

 phoenix 1 23 



Rhizoclonium (No. 7) 77 

 kerneri 77 



RHIZOID: a unicellular or 

 uniseriate root-like fila- 

 ment serving for attach- 

 ment, Fig. 256. 



of net-like 

 (No. 22) 123 



RHIZOIDAL FILAMENT: a 

 very slender, long, thick- 

 walled cell with exceed- 

 ingly small cavity, found 

 in the medulla of certain 

 Gelidiaceoe. The cell walls 

 hove the form of the rub- 

 ber insulation of a heavy 

 duty electric wire. 



Rhodoglossum (No. 126) 154 

 161 

 affine 154, 161 



Rhodomela (No. 162) 66 

 larix 66 

 subfusca 66 



Rhodymenia (No. 132) 164, 

 165, 166 

 pacifica 166 

 palmata 1 66 

 pertusa 167 



Sargassum (No. 79) 110 

 agardhianum 1 1 6 

 filipendula 1 1 

 fluitans 1 10 

 natans 1 1 

 palmeri 1 1 



SAXICOLOUS: growing at- 

 tached to rocks. 



Schizymenia (No. 112) 150 

 pacifica 1 50 



Scytosiphon (No. 51) 97 

 lomentaria 97 



SEGMENTED: divided into 

 segments or joints; articu- 

 lated, as in Corallina sp. 

 Fig. 257. 



Figure 257 



Figure 256 



SEGMENTS: the portions or 

 divisions of a thallus be- 

 tween points of branch- 

 ing; or, specifically in 

 articulated corallines, the 

 calcified portions (inter- 

 genicula) between the ar- 

 ticulations. 



Seirospora (No. 141), 51, 52 

 griffithsiana 51, 52 



SEPTATE: provided with 

 cross walls or partitions. 



196 



