TRANSACTIONS OF SECTION D. 817 



siderable portion of the diameter of the basidium. When division is about to 

 take place the nuclear threads break up into a number of short pieces ; the nuclear 

 granules run together and give these pieces a homogeneous appearance. The mem- 

 brane gradually becomes more and more indistinct, especially at the upper end of 

 the nucleus ; the nuclear threads group themselves at this point and form an equatorial 

 plate, they become shorter and thicker and now stain bright red instead of blue ; 

 the nucleolus persists all this time, but has been gradually getting fainter ; the 

 chromosomes at the same time becoming bright red. A nuclear spindle now 

 appears ; it consists of a few threads, the exact number of which could not be made 

 out ; and in Stropharia stercorarius , but not so clearly in Amanita muscarim, a 

 deeply stained dot (centrosome ?) can be made out at each pole of the spindle. 

 The chromosomes now divide into two groups, which begin to move along the 

 spindle to the poles. The nucleolus has by this time almost entirely disappeared. 

 When the chromosomes reach the poles of the spindle they become condensed into 

 two irregular masses which stain red. A nuclear membrane then appears around 

 each, and from these red masses threads apparently radiate more or less regularly. 

 The nuclei then increase in size, a new nucleolus appears in each, and a distinct 

 network is formed, so that the nuclei now resemble the original nucleus of the 

 basidium. Then these two nuclei begin to divide, the process being exactly 

 similar to the original division, and four nuclei are produced, one for each spore of 

 the basidium. 



7. On Variation of Fecundity in Trifolium pratense and its varieties 

 and Trifolium medium. Bij William Wilson. 



Trifolium pratense. — Purple Clover is known as heing prolific in seeds. While 

 there exist several varieties of it, caused perhaps by the peculiar conditions under 

 which each exists, such as the soil, none of these varieties is so good a seed- 

 producer as the normal type, as far as is known. 



The most important variety, supposed by some to be a hybrid between Purple 

 Clover and Zigzag Clover, and known as Trifolium perenne, Perennial Red, and 

 as the Cowgrass of commerce, has the commercial value of its seeds higher than 

 those of Purple Clover on account of the weakness in seed-producing. Although 

 the plants may yield as many flowers, the seed is deficient, while it has a more 

 penetrating root. 



Touching next upon Trifolium medium, Zigzag Clover or Cowgrass of botany, 

 I find from observations on plants in an endigenous state, and by transplanting, 

 that the seeds are very few in number. 



There is a form of Trifolium, which diifers in characters from all the forms 

 mentioned, which I call Perennial Meadow Clover, which is an abundant seed- 

 producer in its endigenous condition. 



8. On the Cortex o/Tmesipteris tannensis, Bernh. 

 By R. J. Hauvky Gibson, M.A., F.L.S. 



After reference to the existing literature on the subject, the author drew 

 attention to the difference of opinion on the nature and mode of deposit of the 

 brown substance contained in the cells of the inner cortex of Tynesipteris tannen^is 

 (Bernh.) and other species. He supports the view held by Bertrand and Dangeard 

 that the substance is deposited in the cell wall, not in the cell cavity, and showed 

 that by means of suitable reagents and care in manipulation, the presence of both 

 tannin and iron could be demonstrated in the deposit. He suggested the possi- 

 bility of the tannate of iron having been absorbed from the roots of the tree ferns 

 on which Tmesipteris is probably not an epiphyte but a parasite. Evidence was 

 also adduced that there exists in the stem and rhizome of Tmesipteris a true 

 endodermis with cuticularised radial walls, lying between the layer containino- 

 the brown deposit and the pericycle. 



1893. 3 a 



