190 Rhodora [SEPTEMBER 
ATHYRIUM ASPLENIOIDES forma subtripinnatum, forma nov., fron- 
dibus maximis subtripinnatis, pinnulis deltoideo-lanceolatis ad 2 cm. 
longis, 8-10 mm. latis subacutis pinnatifidis, segmentis ordinis tertii 
oblongis obtusis ad apicem dentatis pinnulis parvulis formae typicae 
similibus. 
A rare and unusually large form in which the segments of the third 
order, rather than the pinnules show the characteristic blunt oblong 
form (Plate 123, figs. 5 and 6). 
Specimens in the Gray Herbarium: 
MASSACHUSETTS: rich wet situations in half shade, Coon Hollow 
Brook, Milton, September 19, 1901, F. G. Floyd no. 89 b (N. E.); 
West Tisbury, July 26, 1916, F. C. Seymour. 
West Virani: Glady, Randolph Co., September 21, 1904, J. M. 
Greenman no. 32. 
VircintA: altitude 3500 ft. near Luray, August 15, 1901, E. S. 
and Mrs. Steele no. 233; altitude 3600 ft. near Luray, August 27, 
1901, E. S. and Mrs. Steele no. 48 (Type). 
AA. Rhizome horizontal or somewhat oblique, completely concealed by the 
thick fleshy bases of the old fronds; scales of the stipes usually dark 
brown, their cells very narrow, and with thick usually dark walls; 
frond widest near the middle; indusia usually toothed or short ciliate, 
or rarely long ciliate, never glandular; spores yellow brown, smooth or 
sparingly papillate. 
ATHYRIUM ANGustuMm (Willd.) Presl.! 
Aspidium angustum Willd. Sp. Pl. ed. 4, v. 277 (1810). 
Asplenium Michauxii Spreng. Syst. iv. 88 (1827). 
Asplenium elatius Link, Fil. sp. 94 (1841). 
Athyrium angustum Presl, Rel. Haenk. i. 39 (1825) as to combina- 
tion only, excluding description and specimens cited. 
Asplenium Filix femina var. Michauxii Mett. Uber einige Farngat. 
vi. Asplen. 199 (1859). 
Athyrium asplenioides var. angustum Moore, Index Fil. 179 (1860). 
Athyrium Filix-femina var. Michauxii Burnham, Am. Fern Journ. 
vii. 54 (1917). 
An exceedingly polymorphic species, varying but slightly in the 
characters of rootstock, scales, sori, indusia and spores, but very 
widely, in the form of the frond. On the basis of differences in the 
frond, the following varieties and forms may be recognized, though 
in every case they pass by imperceptible gradations into one another: 
C. Fronds dimorphic, the fertile coriaceous, contracted, sori at maturity 
confluent and covering the lower side of the fertile pinnules. Sun- 
forms, found only in regions of hot summers. 
1 See Plate 123, figures 11-18. 
2 The frequently cited reference of this combination to Mettenius, Fil. Hort. Lips., 1856 is 
not correct. Mettenius there described the variety, but gave it no name. 
