364 
DR JOHN M'LEAN THOMPSON ON THE 
associated with a group of non-indusiate Ferns with the majority of which its 
relationships were not close. In the Synopsis Filicum of 1874 the generic rank 
of Jamesonia was upheld. In 1882 Kuhn ( Die Gruppe der Chsetopterides unter 
der Polypodiaceen ) renamed Jamesonia Psilogramme, and placed it next to 
Gymnogramme. To Christ ( Farnkr .) in 1897 Jamesonia was a true genus; in 
1897, 1902, Diels (Engler and Prantl, Nat. Pfm.) considered the limits between 
Jamesonia and Gymnogramme very conventional ; and in 1905 Christensen ( Index 
Filicum) placed it between Gymnogramme and Coniogramme , Fee. 
No material contribution to the knowledge of the structure of Jamesonia has 
been made. But while opinion has differed regarding species and varieties, the 
Jamesonia of Hooker and Greville has been widely accepted as a genus allied 
to Gymnogramme. The only references to the anatomical condition of Jamesonia 
are in a paper by Dunzinger ( Beitrdge zur Kenntnis der Morphologie und 
Anatomie der Genera Hemionitis , Gymnogramme, und Jamesonia , 1901). This 
author noted a similarity of hairs and spores as existing between Jamesonia and 
certain species of Gymnogramme, and that the slender solenostele of Jamesonia 
is comparable to that of Gymnogramme angustifrons, Bak., but that the cortex 
of the stem of Jamesonia possesses a curious spongy tissue. These observations 
do not seem to form a sufficient basis for Dunzinger’s statement that “ only the 
outward appearance of this xerophytic plant is deceptive, for it is a true Gymno- 
gramme. On this point the anatomical state bears convincing evidence.” 
The facts detailed in the following pages are the result of study of ample 
preserved materials of Jamesonia scalaris, Kze., kindly supplied by Dr Willis, 
Rio de Janeiro, from the Province of Sao Paulo. An herbarium specimen of the 
same species, for which I am indebted to Mr A. W. Hill, M.A., F.L.S., Assistant 
Director, Kew Gardens, has also been examined. This plant was collected in 
1903 on boggy ground at an altitude of 15,000 feet in the Urubamba Valley, 
Pacechac, Peru. As will be seen from Mr Hill’s photograph (fig. 2), the plant 
grows up to the snow-line, and is of a striking appearance. The Jamesonia plants 
are on the left of the photograph and immediately under the rock face. The plants 
on the right are probably Lycopods. Jameson’s statement that this plant grows 
“in marshy places among Sphagnum and at elevations between 8000 and 
14,000 feet” is thus demonstrated. The herbarium specimens of J. verticalis, Kze., 
and J. cinnamomea, Kze., in Glasgow University have also been examined. 
The leaf-habit is admirably suggested in Dr Greville’s original drawing ( Ic . 
Fil.), and the general habit of the plant is shown well in Engler and Prantl 
(Nat. Pfm.). 
Dermal Appendages. — The dermal appendages of the axis of J. scalaris are 
multicellular mounds and slender, golden-brown hairs. The former are irregular 
groups of dark sclerotic cells ; the latter are multicellular, and terminate in thin- walled 
glandular cells. The hairs and mounds are commonly combined, either a single hair 
