THE GENUS POLYSIPHONIA. 
B. More than four primary pericentral siphons. 
1. P. atro-rubescens. 5. P. opaca. 
2. P. fastigiata. 6. P. Richardson. 
3. P. furcellata. 7. P. simulans. 
4. P. obscura. - 8. P. subulifera. 
II. Corticate Species. 
A. Four primary pericentral siphons. 
1. P. elongata. 4. P. fibrillosa. 
2. P. elongella. 9. P. spinulosa. 
3. P. fibrata. 6. P. violacea. 
B. More than four primary pericentral siphons. 
1. P. Brodiai. 4. P. nigrescens. 
2. P. fetidissima. 5. P. variegata. 
9. P. fruticulosa. 
KEY TO SPECIEs. 
. Axis consisting of .4 primary pericentral siphons, with or without 
283 
cortieation . 6... e hmm nn nn en 20 
More than 4 .................,,...... ee es 2 
2. Axis consisting of 5 primary pericentral siphons ................ à 
More than 5 co... ce cee ccc hm 4 
3. Articulations 3 or 4 times longer than broad in lower parts of axis; 
siphons spirally placed... 0... 6.0... eee cee t n P. Richardson. 
Articulations shorter than their breadth near the base; siphons 
irregular... cesse heme nnn P. variegata, 
4. Axis consisting of 6 primary pericentral siphons, with or without 
Cortication 6... m e enn je 8 
More than 6 .........,.,,......., sense essen nern nenne 5 
5. Axis consisting of 7 primary pericentral siphous, with or without 
Cortication oo... hehehe nnn 8 
More than 7... IHR he e een 6 
6, Axis consisting of 8-11 primary pericentral siphons, with or with- 
out cortication .......,.................... boraren ee 7 
More than 11....................,,,...,,,..,..,44444400 11 
7. Zone of cells present in older parts, outside primary siphons...... 8 
Not 80,...........4...,.,.....,44444,,44444 ss 9 
8, Ramuli slender and regularly distributed over the younger branches. P. variegata. 
Ramuli borne close together, giving plant a tufted appearance .... P. Brodie. 
9. Pericentral siphons spirally eurved..,.................,....... P. atro-rubescens. 
Not Te 10 
10. Colour bright brick-red .................................... P. furcellata. 
Colour dark brownish-red ,................................. P. feetidissima. 
11. Axis consisting of 12-14 primary pericentral siphons, with or 
without curtication ,...................,,,.....,,,.,.... 12 
More than 14,,............,,..,.,,.. MENT TM 17 
