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upper surface, surrounded by a folded rim, elongated in one direction. 

 The rim was absent at the two ends of the depression, which, owing to 

 the continued growth of the upper region of the prothallus, had in some 

 cases become curved outwards and downwards. This agrees in all main 

 points with the descriptions whicli Lang (14) and Bruchmann (6) have 

 given of the prothallus of L. clavatum, and Bruchmann also in the case 

 of the prothallus of L. annotinum. The oldest and largest specimens 



Fig. 28. — Lycopodium volubile. Prothalli in position relative to surface 



of ground. X 4. 



sometimes showed one or more secondary folds on the upper surface, and 

 rounded protuberances, which had the effect of almost filling up the 

 original depression (fig. 29). The prothallus shown in fig. 26 was grow- 

 ing at the surface of the ground, and its upper portion was coloured a 

 dark green. Rhizoids are present on well-grown prothalli, especially 

 on the region above the first-formed tapering portion immediately below 

 the rim; but many of the prothalli seemed to be quite destitute of them, 



Figs. 29, 30. — Lycopodium volubile. A very large prothallus ; top and side 



views respectively. X 2h. 

 Figs. 31, 32. — Lycopodium volubile. Exhausted prothalli. X 8. 



and were easily* brushed clean of any adhering particles of soil or pieces 

 of moss. In not a few cases two or three young plants were seen on 

 the same prothallus. Figs. 31 and 32 show two exhausted prothalli, 

 in which the long tapering first-formed erect-growing portion is very 

 obvious, the upper part of the prothallus being flattish and slightly 

 concave, and the rim sharp. The depleted prothallus shown in fig. 32, 

 when viewed from below, showed between the tapering portion and 

 the upper flat region a narrow ridge which corresponded in direction to 



