3i 7 
/ 
of Lycopodium clavatum , L. 
Fig. 22. Transverse section of the neck of an opened archegonium. x 375. 
Fig. 23. Prothallus bearing a young plant, seen from the end. x 7 * 
Fig. 24. Prothallus, the irregular shape of which is probably the result of an 
injury, bearing two young plants of similar age ; from above, x 7* 
Fig. 25. Section of one of the young plants in Fig. 24 in the median plane of 
the root, x 25. 
Fig. 26. Similar section of the young plant in Fig. 24 in a plane at right angles 
to that of the root, x 25. 
Figs. 25 and 26 demonstrate the absence of the protocorm ; in both the 
extent of the absorbent layer of the foot is indicated by shading. 
Fig. 27. Portion of the foot of one of the young plants in Fig. 24, showing the 
absorbent layer of cells bounding it ; these are seen to be densely filled with 
protoplasm, x 200. 
Fig. 28. Section through the region of attachment of the young plant in 
Fig. 23 to the prothallus in the plane of root and shoot. The tissue of the 
prothallus is uniformly shaded. x 80. 
Figs. 29, 30. The region of attachment to the prothallus of two young plants 
to show the differences in form and position of the foot, x 7. 
Fig. 31 a, b, c. /Stages in the origin of the ‘ multinucleate vesicles ’ from the ends 
of hyphae of the mycelium within the cells of the prothallus. x 1,000. 
Fig. 32. Cell from layer b of the prothallus, showing a multinucleate vesicle, 
close to which the nucleus of the cell is seen presenting a healthy appearance, 
x 1,000. 
Fig. 33. Cell from the same layer, showing coarser hyphae, two of which are 
seen to expand into multinucleate vesicles, x 1,000. 
Fig. 34. Older cell from the same layer, showing the disorganized mycelium 
in which bodies resembling spores are visible, x 1,000. 
Fig. 35. Basal portion of a rhizoid in optical section, showing two hyphae 
passing into the cavity of the rhizoid from the tissue beneath, x 375. 
Fig. 36. Section through the basal portion of a rhizoid, showing the entrance 
into its cavity of two hyphae which receive short tubular sheaths on passing 
through the wall, x 750. 
Y 
