Bower.—Studies in the Phytogeny of the Fiticales. VII. 57 
for in specimens of Dennstaedtia dissecta (Sw.), Moore, taken in Jamaica, 
bulbils were found in a similar position. Their presence had already been 
noted by Jen man in D. rubiginosa , especially in plants from the higher 
elevations (‘Synoptical List of Jamaican Ferns’). An examination of the 
further details in Monachosorum may then start on a working hypothesis 
of its relation to the Dennstaedtiinae, and especially to Dennstaedtia and 
Microlepia. 
The relatively thin ascending axis bears laxly crowded leaves, and axis 
and leaves bear simple ferrugineous hairs, not scales. This accords with the 
Dennstaedtiinae, and marks it off from Davallia on the one hand, and from 
Polypodium on the other. Transverse section of the axis shows a dictyostele 
Fig. 43. Pinnule of Monachosorum subdigi- 
tatum in surface view, (x io.) 
Fig. 42. Transverse section of 
the stock of Monachosorum sub- 
digitatum. ( x 4.) 
but very slightly removed from a solenostelic state (Fig. 42). The leaf- 
trace comes off as a very broad but thin strand, leaving a leaf-gap which 
very soon closes. The mode of its origin, by dilation and thinning of a region 
of the solenostele, closely resembles what is seen in Denn. apiifolia,adiantoides , 
or cicutaria , as shown in Gwynne-Vaughan’s preparations. As the leaves are 
closely aggregated on the oblique rhizome, the leaf-gaps overlap in Monacho - 
sorum , two or three being present in a single transverse section. Such a 
dictyostelic state would be the natural result of the shortening of the internodes 
in an obliquely ascending stock like that of Monachosorum , starting from an 
elongated solenostelic stock such as that of the simpler Dennstaedtiinae. 
Before the leaf-trace actually separates it may have already parted in its 
median plane to form two isolated straps. But this is not constant. Some¬ 
times the transverse section of the leaf-trace may be already divided into two 
