456 III. SEGREGATES AND 
the two ferns we now know as dilatata and spinulosa. It is not 
conceivable that London botanists had seen only one of those two 
plentiful ferns before the end of the eighteenth century ; but, like 
leading botanists of this time, they doubtless held them forms of a 
single species. 
In the ‘ Flora Britannica,’ 1804, we find a dual division into 
the spinulosa and dilatatu as now understood,—the Polypodium 
rheticum of Hudson alluded to as seemingly a variety of dilatata, 
—a declaration that the cristata of Linneus is a species quite 
distinct from those,—with a compliment to Withering as the 
elucidator of spinulosa. This was a good advance beyond Hudson ; 
but unfortunately succeeding botanists retrograded into confusion 
again. In ‘English Flora,’ a quarter century later, the dual 
division of its Latin predecessor was made tripartite by addition of 
a supposed third species under name of dumetorum, a fern which 
has since led to considerable discussion. On faith of the Banksian 
herbarium the rhaticum of Hudson is quoted as synonymous, and 
it may be so. 
By some fern-men it has been thought that Smith’s dumetorum 
was the more modern species @mula. (See Newman’s ‘ History,’ 
pages 60 and 61 of first edition, page 230 of second edition). 
I assume this to have been a mistake, relying on the evidence of 
five fronds sent by Shephard to Smith, from a Derbyshire root 
cultivated in the Botanic Garden of Liverpool; also, of one frond 
picked by Dr. Godfrey Howitt, in “ Smith’s original locality of 
Cromford Moor,” as stated on its label in my herbarium. These 
six fronds all belong to dwarf dilatata. The garden specimens are 
conspicuously convex (not concave or recurve) on their upper 
surface, their outline is not triangular as in @mula, and the scales 
on the stipes are dark and entire. They were found among 
miscellaneous plants bought at the sale of the Linnean Society’s 
collections ; and putting little circumstances together, I inferred 
that they had been sent to Smith in the year 1825. They are 
passally represented by Newman’s figures of dumetorum on page 
60 of the first edition, especially the upper figure, which is given 
for nana on page 222 of the second edition, repeated on page 153 
