78 SUMMARY OF CURRENT RESEARCHES RELATING TO 



same prothallus. The antherids were large, and often closely crowded 

 together ; they hardly projected from the surface ; the wall being only 

 slightly convex. The archegonial neck, which was formed of four rows of 

 cells, projected distinctly from the prothallus. An endophytic fungus 

 occupied a wide zone in the basal part between the two or three superficial 

 layers of cells and the central tissue, but was entirely absent from the re- 

 productive region. The young plants attained a considerable size while 

 still attached to the prothallus. 



Psilotum sp. (The single prothallus found was not in genetic con- 

 nection with a sporophyte, and may possibly belong to a Lycopodium.) 

 The prothallus was about £ in. in length by about y\ in. at the widest 

 part. The lower portion is cylindrical and rounded below ; on one side 

 near the lower end is a well-marked conical projection directed obliquely 

 downwards. Ehizoids were borne on the lower three-fourths of the 

 prothallus, but were absent from the upper part. In the tissue of the 

 overhanging margin the numerous sunken antherids occur, closely 

 crowded together. No archegones were seen. 



Fibrovascular Bundles in the Stem and Leaf of Filicineae. * — 

 C. E. Bertrand and F. Cornaille point out that in the stipe and leaf of 

 Filicineae (Megaphyllidae) the conducting tissue occurs in the three 

 following forms : — (1) a bipolar bundle ; (2) a diverging bundle, which 

 may be closed or reduced to the condition of a bipolar mass ; (3) an 

 indeterminate fibrovascular mass or bundle. The first form is repre- 

 sented in the foliar trace of Osmunda ; the second in that of Cyathea 

 medullaris. The third form has a concentric structure ; the tracheae 

 are central in relation to the xylem, this latter being surrounded by 

 a phloem. The bipolar bundles of the Filicineae are usually convex 

 towards their anterior face ; this convexity may be slight, but never 

 disappears altogether. A divergent bundle may have very unequal 

 wings. When the anterior phloem is greatly reduced, it may assume 

 the aspect of a unipolar bundle. When the indeterminate fibrovascular 

 masses are destitute of tracheae, they are termed by the authors "apolar." 

 Divergent and bipolar bundles unite laterally into fibrovascular chains. 

 A chain is continuous when there is no solution of continuity in its 

 xylem between its extremities ; discontinuous when there is such a 

 solution; dialy divergent when all its divergents are independent in 

 their xylem portion. A chain is open when its extremities are separated 

 from one another. An example of a closed dialy divergent chain is 

 afforded in the external arc of the foliar trace in the centre of the petiole 

 of Helminthostachys zeylanica. 



Germination of Fern-Spores, f — A. Burgenstein confirms the state- 

 ment of most previous observers, that a certain amount of light is 

 necessary both for the germination of the spores of ferns (Pteris) and 

 for the development of the prothallus. Under favourable conditions 

 the spores of ferns will, however, retain in the dark their power of 

 germination for many weeks. The conditions of germination are, 

 therefore, not the same for fern-spores as for seeds. 



* Comptes Eendus, cxxxiii. (1901) pp. 524-6, 546-S, 695-S. 

 t Wien. illustr. Gartenzeit., 1900, 2 pp. See Bot. Centralbl., lxxxviii. (1901) 

 p. 105. 



