184 SUMMARY OF CURRENT RESEARCHES RELATING TO 



bulbifera, Asplenium bulbi/erum, &c), with that of regenerating buds 

 on isolated scales of the adventitious buds of C. bulbifera, and on the 

 detached bases of the fronds of various species of Cystopteris ; — the 

 former begins with the activity of a single epidermal cell ; the latter 

 with divisions in a larger number of epidermal cells. The adventitious 

 buds or gemmse are formed occasionally and singly at definite spots on 

 the plant ; the regenerating buds may arise in large numbers in close 

 proximity to one another. Transitional forms occur between the two 

 kinds of bud. 



Achromatic Spindle in the Spore-mother-cells of Osmunda. * — 

 E. Wilson Smith has followed out the formation of this structure in 

 the case of Osmunda regalis ; the following are the more important 

 points brought out. 



The achromatic spindle arises wholly from cytoplasm, which accu- 

 mulates about the nucleus in the synapsis or spirem stage in the form 

 of an indefinito granular mass of staiuable matter. The kinoplasrn 

 becomes distinctly granular ; then the granules arrange themselves into 

 short rows concentric with the nuclear membrane ; finally the rows of 

 granules are massed in greatest abundance on opposite sides of the 

 nucleus. The spindle is bipolar from the beginning ; usually one pole 

 is formed considerably in advance of the other. The fully formed 

 spindle shows no distinction of central and mantle fibres, and no bodies 

 which can be interpreted as centrospheres. The dissolution of the 

 nuclear membrane is attended by a sudden narrowing and a correspond- 

 ing increase in length. During the anaphase new secondary fibres are 

 put forth about the poles, and meet in the equatorial region of the 

 cell. In the late anaphase the primary fibres, and soon after them the 

 secondary fibres, begin to disintegrate, taking the appearance of beaded 

 threads, and then of granules. The spindles of the second division are 

 constructed out of the granular products arising from the disintegration 

 of the first spindle. The phenomena of the second spindles exactly 

 repeat those of the first, except that four secondary spindles are formed 

 by the union of the secondary fibres put forth during the anaphase, 

 ('ell-plates are formed across the six spindles, and in connection with 

 them the separating walls of the spores are laid down. 



Fructification of Palaeozoic Lycopods. f — Dr. D. H. Scott states 

 that the bodies from the Coal-Measures described by Williamson under 

 the name Cardiocarpon are really the fructification of a Lycopod, which 

 occupies the boundary line between Spermaphytes and Sporophytes. 

 He proposes for it the generic name Lepidocarpon g. n., with the follow- 

 ing characters. Strobilus with the characters of Lepidostrobus, but 

 microsporanges and megasporanges each surrounded by an integument, 

 growing up from the upper surface of the sporophyll ; megasporange 

 completely enclosed in the integument except for a slit-like micropyle 

 along the top ; a single functional megaspore developed in each mega- 

 sporange ; sporophyll, together with the integumented megasporange, 

 detached entire from the strobilus, the whole forming a closed seedlike 

 reproductive body. 



* Bot. Gazette, xxx. (1900) pp. 361-77 (1 pi.). 



t Proc. Roy. Boc, lxvii. (1900) pp. 306-9. Ann. of Bot., xiv. (1900) pp. 712-6. 



