872 REPORT— 1897. 



Osmundacere. The cotyledon begins to assimilate as soon as it reaches the surface 

 of the ground, and thus resembles that of Oiihioglossum j^edunculosuin. 



There seems to be no evidence to indicate that more than the cotyledon appears 

 above ground in the first season of the young plant's growth. In following 

 summers apparently only a single leaf is produced, as is the ease with the older 

 plant. I have found young sporophytes, bearing their sixth leaf, still attached to 

 the mother prothallium : and, as I have never found more than one leaf on the 

 spore plants at once, and as the leaves, like other organs of this species of Botry- 

 chium, are extremely resistant to decay, I am reasonably certain that such examples 

 were in the sixth year of their existence. This longevity of the gametophyte is of 

 some interest. 



One frequently finds two sporophytes on a single prothallium, and in many of 

 these cases the apex of the prothallium is bifurcated. In one case I found two 

 spore plants which had arisen from a single embryo. In another case I discovered 

 two tracheids in a prothallium in the vicinity of a decayed young spore plant. 

 The latter may have been of apogamous origin, as a similar phenomenon generally 

 accompanies apogamy. I have not yet studied thoroughly the growing region of 

 the prothallium, as it is best examined in longitudinal sections of the gametophyte. 

 So far as I have investigated the matter, there seems to be evidence of the existence 

 of an apical cell. 



2. Eemarks on Changes in number of Sporangia in Yascidar Plants. 

 ^ By F. O. Bower, F,R.S. 



Comparison shows that in certain cases a progressive increase in number of 

 sporangia has taken place, in others a decrease. The changes may be classified 

 as follows : — 



Increase in Jiumber of sporangia. 



Directlv /(''') ^^.>' septation of sporangia. 



I. (&) hy intei-polation of sporangia. 



r (c) by continued apical or intercalary growth of the part bear- 

 Indirectly <; ing the sporangia, with or without branching. 



I, (d) by branchings in the non-sporangial region. 



Decrease in number of sporangia. 



Directly ■f^*') ^^- ^"®''''? °^ sporangia. 

 •' \{h) by abortion of sporangia. 



{(e) by reduction or arrest of growth or branching of the part 

 bearing the sporangia. 

 {d) by suppression of branchings in the vegetative region, 

 resulting in fewer sporangial shoots. 



_ Probably this does not exhaust the list of modes of modification, but the con- 

 dition of the individual plant, as we see it in the mature state, may be regarded 

 as a resultant of modifications such as these, and the morphological problem will 

 be in each case to assign the due importance to any or all such factors. The 

 physiological condition of the plant during development may largely determine 

 the greater or less prominence of any one factor. 



An analytical study such as this may help in clearing the problem of the origin 

 of homosporous Pteridophyta. 



3. Notes on Fossil Equisetaceoi. St/ A. C.Bewarb, M. A., F.G.S., Cambridge. 



The genus Equisetites, established by Sternberg in 1838, has been used by 

 several authors as a convenient designation for fossil Equisetaceous stems,^ which 

 show a close agreement in external form with the recent Horse-tails. In the 



