202 MR. A. W. HILL—REVISION OF 
In nearly every specimen the underground stem is branched and each branch is 
surmounted by a rosette of leaves, which may be closely aggregated to form dense 
compact masses or loosely arranged in lax and spreading rosottes: Oving to the close 
packing of the branches the separate plants often form little hard cushions of several 
centimetres in diameter. 
A well-marked branched aerial stem occurs in N. Lobbiz, while both N. compacta and 
N. clandestina appear to have their caudices branched above ground. 
In some cases (e.g. NV. Azorella, &e.) the branches may be arranged more or less 
vertically (Pl. 27. fig. 3), giving rise to a firm, hard, hemispherical cushion, while in 
others, e. g. N. pichinchensis, the branches may take the form of horizontal stolons and the 
plants then tend to form an even carpet over the ground ; branching of this character is 
Nototriche turritella on the side of El Misti, Arequipa. 
shown also by the annual species N. pusilla (Pl. 29. fig. 20). In certain species the 
stem apparently does not branch; this is more partieularly the case in the forms with 
bipinnatifid leaves, where the plants usually form small isolated somewhat lax and 
spreading rosettes. 
The underground stem often attains to a considerable length and thickness, being as 
much as 2:5 cm. in diameter in one of Weberbauer's specimens of N. sulphurea, whilst 
in my own specimens of N. turritella it measured 1-1:5 em. in diameter and, including 
the root, over 60 cm. in length (Pl. 27. fig. 2). 
Of this length it seems that nearly 40 em. belong to the stem proper, judging from 
what appear to be the remains of the leaf-scars between the ring-like markings due to the 
contraction of the stem. If a perfect specimen had been obtained it is probable that the 
