1907] Flora of the Boston District, — I 83 
A. acrostichoides Sw. (A. thelypteroides Michx.) Rich woods; occa- 
sional in the northern towns, less frequent southward. 
A. Filix-femina (L.) Bernh. Usually in damp woods and shaded 
places, though occasionally in drier situations; common and 
varying much with the conditions of soil, moisture, and shade. 
Var. angustum (Willd.) D. C. Eaton. Woods, occasional. 
CAMPTOSORUS. 
C. rhizophyllus (L.) Link. Granite ledges, Needham, where observed 
as eirly as 1877; formerly also on Doublet Hill, Weston. 
POLYSTICHUM. 
P. acrostichoides (Michx.) Schott. (Aspidiwm acrostichoides Sw.) 
Rocky woods, distributed here and there, but not very common. 
Var. Schweinitzii (Beck) Small. (Var. incisum Gray.) Amesbury 
(J. W. Huntington); Andover (A. S. Pease); Blue Hills (E. F. 
Williams). 
ASPIDIUM. 
A. Thelypteris (L.) Sw. Swamps, common everywhere. | 
Forma Pufferae (A. A. Eaton) B. L. Robinson in herb. Nephro- 
dium Thelypteris, forma Pufferae A. A. Eaton. Border of 
meadows, Sudbury (Mrs. J. J. Puffer). See Eaton, Fern 
Bull. x, 78. 
A. simulatum Davenp. Swampy woods; locally abundant; often 
associated with the preceding and with Woodwardia areolata. 
See Davenp. Bot. Gaz. xix. 494, 495. 
A. noveboracense (L.) Sw. Low open woods, common. 
A. marginale (L.) Sw. Rocky woods, common throughout. Var. 
ELEGANS J. Robinson (Bull. Essex Inst. vii. 51) is a luxuriant form 
with the pinnules more deeply crenate-toothed. This form not 
very sharply distinguishable from the type has been found at 
Ipswich (Oakes), Swampscott (J. Robinson), and Milton (F. G. 
Floyd). 
A. Boottii Tuckerm. Low woods, frequent. 
A. cristatum (L.) Sw. Open and wooded swamps; frequent: reported 
as abundant in Brockton, Easton, and in northern Essex County. 
Var. Clintonianum D. C. Eaton. Wooded swamps, occasional; 
not reported from open land. Not so extreme as the more 
northern and western specimens. 
