2 Lang, Vascular Anatomy of the OpJiioglossacecB. 



and leaf-trace, this has not been fully studied in the light 

 of that of the extinct Coenopterides. Examination of a 

 considerable number of species of Ophioglossacea^ has 

 led me to regard the anatomy of the rhizome as best 

 interpreted in the light of that of the Coenopterideae and as 

 affording important evidence in favour of a relationship 

 between the two groups. Since it will be necessary to 

 publish the results of my work on the three genera of 

 Ophioglossacea; separately, it appears advisable to make 

 a brief general statement on the comparisons to which I 

 have been led and on the chief grounds upon which they 

 are based. Detailed figures will accompany the full 

 papers, and only a few diagrams will be given here in 

 order to make the comparisons clear. 



The underground stem or rhizome in all the three 

 genera of Ophioglossaceae {Hciiuint/iostachys, Botrychhun, 

 and Ophioglossmn) is normally unbranched. The presence 

 of vestigial buds in the axil of every leaf of HelniintJios- 

 tachys was discovered by Gwynne-Vaughan, and I have 

 recently found that similar vestigial buds are of constant 

 occurrence in Botrychium lunaria^ The anatomical rela- 

 tions of the actual branches, which under special circum- 

 stances spring from these dormant buds, are of considerable 

 interest. Apart from the particular relation of the bud to 

 the leaf-trace or to the stem, however, the regular occurrence 

 of axillary branching in these species is important as 

 strengthening the comparison with the Zygopterideae and 

 Hymenophyllaceai. Whether, as seems possible, the 

 branching which occasionally occurs in Ophioglossuvi can 

 be brought into line with the process in the other genera 

 must be left an open question for the present ; the 

 branches are usually regarded as springing from lateral 

 roots in the case of OpJiioglossinn. 



' Proi. Manchcstei- Lit. and Philos. Soc, Feb. 20th, 1912. 



