870 REPORT— 1897. 



support of large leaves, and hence is to be called phyllosiphonic. In the Lyco- 

 podiales, and probably the Equisetales, it is related to the support of branches, 

 and hence may be termed cladosiphonic. 



WJEDNESDAT, AUGUST 25. 



The following Papers were read : — 



1. The Gametophyte q/ Botrychium virginianum. 

 By Edward C. Jeffrey, B.A. 



A complete description of the gametophyte of the Ophioglossacese has long 

 been a desideratum. 



Since the discovery by Mettinius, in 1856, of the subterranean prothallium of 

 Ophioglossum pedunculosum, and by Hofmeister, in 1857, of that of Botrychium 

 lunaria, nothing has been added till recently to their necessarily incomplete 

 accounts of the gametophyte in these species. Our latest knowledge on this subject 

 is derived from a brief description of incomplete material of the prothallium of 

 Botrychium virginianum found in 1893 at Grosse Isle, Michigan, by Professor 

 Douglas Campbell, which was published in the ' Proceedings ' of the Oxford meeting 

 of the British Association in 1894, p. 695. 



During the summer of 1895 the writer secured a large number of prothallia of 

 the same species at Little Metis in the Province of Quebec. On examination it was 

 found that the material thus obtained aflbrded a complete elucidation of the 

 development and structure of the antlieridia and archegonia, and a less satisfactory 

 series of stages in the segmentation of the embryo. Last summer the remaining 

 prothallia were removed to the number of about six hundred ; and, although they 

 have only been partially studied, owing to technical difficulties in embedding 

 them, yet those examined have supplied all the lacking stages of the development of 

 the young sporophyte 



It is proposed at the present time to furnish a brief account of the features of 

 interest ; a fuller description will shortly appear in the ' Transactions ' of the 

 Canadian Institute. 



The gametophyte of Botrychium viryiniamnn is of flattened oval shape, the 

 narrower end of the prothallium being terminated by the growing point. My 

 examples are from two to eighteen millimetres in length, by one and a-half to eight 

 millimetres in breadth. Their thickness increases from the growing end backwards. 

 The sides and lower surface of the prothallium are covered in younger specimens 

 with multicellular hairs. In older plants these tend to disappear. The middle of 

 the upper surface is occupied by a well-defined ridge, upon which the autheridia 

 are situated. The archegonia are found on the declivities which slope away from 

 the antheridial ridge. 



As might be expected, the younger sexual organs are found nearer the growing 

 point than those of greater age. 



A cross section of the prothallium reveals to the naked eye the fact that the 

 lower part of the gametophyte is composed of tissue which is yellowish in colour, 

 and from which a thick oil exudes, even when the plant has been lying in 90 

 per cent, alcohol for months. The upper portion of the prothallium tissue, upon 

 which the generative organs are situated, is white in colour and free from oil. A 

 long section of the prothallium shows the same distribution of yellow oil-bearing 

 and white oil-free tissue as the cross section, but demonstrates that the oil- 

 bearing stratum is both absolutely and relatively much thicker in the older parts 

 of the plant. 



Microscopic examination shows that the oleiferous tissue has its cells occupied 

 by an endophytic fungus and a very abundant protoplasm. 



The fungus, so far as it has yet been studied, seems to be a sterile Pythium, 

 possibly the same as that found by Treub, Goebel, and others in the prothallium 



