136 BOTANICAL GAZETTE [FEBRUARY 
32. VAN Hook, J. M., Notes on the division of the cell and nucleus in liverworts. 
‘Bot. GAZETTE 30: 394-398. pl. 3. I9Q00. 
33- VOcuHTING, H., Ueber die Regeneration der Marchantieen. Jahrb. Wiss. 
Bot. 10: 367-414. pls. 12-15. 1885. 
EXPLANATION OF PLATES V-IX. 
All drawings, except fig. 7, were made with camera lucida. Figs. 8—52, with 
Bausch & Lomb oculars and ee: as follows: Figs. 8, 10, II, I in. hie 
2 objective; 9 and 25 2 in. oc., $o0r; ; IQ, 21-24, 26, 32, 33; 2 Muoc., 7. .enie 
12-18, 20, 27-31, 34-52, I im. oc., yy obj:; Figs: 53-73 with Zeiss. oc. 7 ou 
apochromatic objective, 1.40 aperture. 
The figures of plate VI were reduced slightly more than one- ee | in repro- 
duction. 
All figures are of Riccia natans except the spore mother-cells (figs. 34-47) 
which are of Riccia crystallina. 
PLATE V. 
Fic. 1. Rosette of plants growing on the soil; a, natural size; 0, enlarged. 
Fic. 2. Land plants growing in regular clusters. 
Fic. 3. Two plants growing on soil, one of which has been injured and has 
grown out in an irregular way from the growing point. 
Fic. 4. New plants growing from apical cells of old thalli. 
Fic. 5. a, Decay of older part of thallus of the land form to give the floating 
form; 0, plants collected in May. If these thalli should become stranded on the 
mud and growth should continue rosettes would be formed. 
Fic. 6. Plants decolorized in alcohol. The sporophytes appear as chains of 
dark bodies in the thallus. 
PLATE VI. 
Fic. 7. Longitudinal section of thallus parallel to the dorsal furrow, showing 
arrangement of sexual organs. 
Fic. 8. Cross-section of thallus showing archegonia. 
Fic. 9. Cross-section of thallus, showing the origin of archegonia in rows on — 
floor of dorsal groove. 
Fic. to. Cross-section of thallus, antheridia. 
Fic. 11. Longitudinal section of thallus parallel to surface, showing the 
arrangement of antheridia. Archegonia have not begun to develop. 
Fics. 12-18. Stages in development of archegonium. 
Fic. 19. Archegonium in which egg-cell has not been fertilized and is 
shrunken. 
Fic. 20. Cross-section of neck of archegonium. 
Fic. 21-25. Stages in development of sporophyte. 
Fic. 26. Spore mother-cells. 
Fics. 27-33. Development of antheridium. Figs. 27-31, from material 
collected in October. 
