NEW SPECIES OF GREEN ALGAE 
301 
EXPLANATION OF PLATES XXV-XXIX 
Plate XXV 
Fig. I. Fertile cells of Zygnefna Collinsianum showing variable position of 
zygospore in one or the other filament, or in the tube. 
Fig. 2. Mature zygospores of Zygnema Collinsianum. 
Fig. 3. Mature aplanospore and rhizoid of Zygnema Collinsianum. 
Figs. 4-8. Vegetative cells and aplanospores of Spirogyra Narcissiana.. 
Figs. 9-1 i. Spirogyra rectangularis. 
Figs. 12-13. Spirogyra pratensis forming aplanospores. 
Fig. 14. Lateral conjugation in Spirogyra pratensis. 
Plate XXVI 
Fig. I. Scalariform conjugation in Spirogyra pratensis. 
Fig. 2. Usual form of vegetative cells of Spirogyra pratensis. 
Figs. 3-4. Spirogyra cafenaeformis var. parvula. 
Figs. 5-6. Spirogyra circumlineata. 
Fig. 7. Spirogyra punctiformis . 
Figs. 8-9. Spirogyra velata var. occidentalis. 
Plate XXVII 
Fig. i. Spirogyra ellipsospora. 
Fig. 2. Two views of spore of Spirogyra ellipsospora var. crassoidea. 
Fig. 3. Vegetative cell of Spirogyra submaxima showing mucilaginous sheath. 
Fig. 4. Zygospores of Spirogyra submaxima. 
Plate XXVIII 
Figs. 1-3. Stages in conjugation of Spirogyra illinoiensis. 
Fig. 4. Mature spore of Mougeotia tumidula. This figure is drawn to a larger 
scale than the others, 10 mm. = 25 
Fig. 5. Oedogonium pauco-costatum. 
Plate XXIX 
Figs. 1-5. Oedogonium praticolum. 
Figs. 6-8. Oedogonium illinoienie. 
Figs. 9-12. Oedogonium pratense. 
Scale of all drawings, with exception of one noted above, 10 mm. = 45 jj.. 
