1902] Davenport, — Notes on New England Ferns — IV 53 



writing (Feb. 5th) brown and withered, but stipes partially standing ; 

 sterile fronds prostrate and green. Normal fronds broadest above 

 the middle, resembling no. 5 below, and no. j(3 above, the lobes 

 more deeply toothed than in no. 5, and less sharply so than in no. 

 7/3. Indusium when found finely glandular. Swamps with nos. 5 

 and 7, Me., N. H., Vt., Mass., R. I., Ct. 



7. Nephrodium spinulosum Desvaux (Aspidium Swz.). Fronds 

 with the divisions all spinulosely toothed, and more deeply cut than in 

 other members of the group. Widely distributed in various situations, 

 Me., N. H., Vt., Mass., R. I., Ct. 



Many forms of this protean species have been found, but the follow- 

 ing are all that appear worthy of permanent recognition. 



a. Normal form. — Whole frond smooth, pinnae obliquely set to 

 the main rachis, the lowermost pair shortest ; sori terminal on the 

 veinlets which terminate within the radius of the fruit-dot (sorus) ; 

 indusia smooth; scales of the crosiers light brown. 



ft. Var. intermedium, Davenport. Divisions of the lamina more 

 finely cut, pinnae spreading at right angles; under surfaces and 

 indusia finely glandular especially along the darker rachises and mid- 

 nerves ; sori below the apex of the veinlet which extends beyond the 

 radius of the fruit-dot ; scales of the crosiers darker. 



y. Var. diiatatufn, Baker. Nearly as in a, but much larger every 

 way, the mountain forms being broadly triangular ovate ; sori below 

 the apex ; scales on the crosiers dark with blackish centres on some 

 of the largest forms. 



Obs. As is well known Nephrodium dilatatum is considered by 



English authors generally as being a wholly distinct species from N. 

 spinu/osum, and even Moore, who yet regarded spinulosum as a mere 

 variety of cristatum, so treated it under Lastrea, describing several 

 forms as varieties. His description of var. tanacetifolia "fronds 

 ample, triangular or sub-triangular ovate, tri-quadri-pinnate ; scales 

 of the stipe dark-centred" (Native Printed Ferns 1, 225) exactly 

 fits our mountain forms from New Hampshire and Vermont ; but 

 Moore's forms are all described as having glandular indusia, whereas 

 in our form the indusium is smooth as in a. 



8. Polystichum acrostichoides, Schott (Aspidium, Swartz). 

 Christmas Fern. Whole plant remaining green, or nearly so; fertile 

 fronds contracted above the middle, the tips only perishing ; pinnae 

 auricled at the base, spiny toothed. Rocky hillsides and ravines, Me., 

 N. H., Vt., Mass., R. I., Ct. 



