uo oup CAT o, T. * mu fel ANNO 4 
1915] Fernald,— Dryopteris spinulosa, var. dilatata 45 
European plant with glandular indusia and have so generally main- 
tained it for the American plant with glabrous indusia. So fixed has 
been this tradition among American fern-students that, when the 
late B. D. Gilbert found an exceptional plant with glandular indusia, 
supposed by him to be an extreme of D. dilatata, he wrote: 
“ Babington, Sowerby, Smith, Moore, Hoffmann, Presl, DeCandolle, 
and most of the older botanists, regarded this [D. dilatata] as a distinct 
species. But all of them, whether they considered it a species or a 
variety, characterized it as having an ‘indusium fringed with stalked 
glands.’ American botanists, however, from an early period, made the 
point that the indusium was ‘smooth and naked,’ and this has been 
insisted upon as an indispensable requisite of the variety in this coun- 
try. But is it so? If it has indusia with stalked glands in Europe, 
why may it not have them in this country also? It seems to me that 
the distinction is false, and cannot be regarded as imperative. The 
mere fact that much of the dilatata found here has a naked indusium 
does not preclude the possibility of a form that may agree with the 
English form." ! Gilbert then goes on to identify his unusual Ameri- 
can plant with glandular indusia not as D. dilatata (true) but as 
Lastraea dilatata, var. glandulosa Moore or, as he renamed it, Dryop- 
leris spinulosa glandulosa. 
The writer is not at all confident that the American plant called by 
Gilbert Dryopteris spinulosa glandulosa and subsequently renamed by 
him Nephrodium spinulosum fructuosum? has much in common with 
the plant of Moore; but Gilbert’s argument, above quoted, does not 
change the fact that glandular indusia are practically unknown in the 
common plant of northeastern America now passing as D. spinulosa, 
var. dilatata. This is obvious not only from close study of the speci- 
mens, but from the writings of Gray, Eaton, Davenport, and a host of 
students of the present day; and in 1907 this common American plant 
was distinguished as Aspidium spinulosum, var. dilatatum, forma 
anadenium Robinson, RHopora, ix. 84 (1907). 
The chief object of the present note, however, is to call attention to 
a much more obvious character in which our plant departs very con- 
stantly from the European var. dilatata. In the common American 
plant the ovate or lanceolate scales of the stipe are very thin, trans- 
lucent and soft in texture (like tissue paper), of a pale brown or slightly 
1B. D. Gilbert, Fern Bull. viii. 10 (1900). 
2 Gilbert, List N. A. Pterid. 37 (1901). 
