BRITISH FERNS 
LXXXI 
REVOLVENS (Moore) 
Mr. Jno. Wills. Somerset. 1872. 
1 tht, © wm, 
Mr. Lucas, of Balham, was the first to notice this variety in 
Sussex and it was then named arctatum. It has since been 
frequently found by Mr. Wills, Mr. Moly, Mr. Padley, and Mr. 
Wollaston in S. Devon, and in the adjoining parts of Somerset 
and Dorset it was also found to a considerable extent and jn good 
form in Hampshire by Major Jones. Among the most marked 
forms of this variety are a fine crispate form, found by Mr. Padley, 
a sub-plumose form, by Mr. Moly, and one with reflexed pinnules 
by Mr. Wills, who has also been the discoverer of some of the 
most characteristic of the simpler forms. 
Mr. Wollaston attributes the revolvens habit (as also that of 
reflexum (when in excess), and even that of Jlexuosum) to < the 
natural tendency of all Ferns to protect their fructification from 
too great an exposure to sun and rain.” 
Mr. A. Leipner has supplied the following suggestions towards 
an explanation of the flexuose habit: “In a leaf the ultimate 
number of cells is already present whilst in a bud, and the develop- 
ment of the leaf consists of a differentiation of these different cells 
into the various forms and sizes as present in the parenchyme and 
fibro-vascular bundles. 
“Мау not in Ferns the same hold good and the flexuose form be 
produced by an extreme elongation of the wood cells and in the 
rachis?” 
Mr. Wollaston adds, ** The flexuose habit both in Ferns and trees 
must arise from the unnatural expansion or contraction of one 
part or parcel in excess to the prejudice of the others—and that 
this abnormal growth is caused by the extreme elongation of the 
wood cells in the rachis.” 
Mr. J. Morris writes: 9 I am much more disposed myself to 
think cell division is the secret, but what is the cause of cell 
division abnormally copious and how is it inherited ? ” 
Mr. Е. Е. Fox supports Mr. Morris’s opinion. 
Whatever doubts there may be on this point, there can be no 
doubt that it will for a long time hold its own among Ше first 
dozen of the most beautiful of British Ferns. 
The Rev. H. Aubrey has suggested the idea that the flexuose 
character is a preparatory attempt on the part of these varieties to 
adopt the climbing habit. 

