1913] The Ottawa Naturalist. 97 



ASPIDIU.M SPINULOSUM Var. INTERMEDIUM (Muhl.) D. C. 



Eaton (Spinulose Wood Fern), and Aspidium marginale (L.) 

 Sw. (Evergreen Wood Fern). Both of these ferns thrive well in 

 a moist, typical "cedar swamp," with a mucky soil. They are 

 usually shaded in such a habitat by cedar, hemlock, black ash 

 and mountain map! The latter species is impatient of too 

 dense shade and will thrive in a fairly open situation. The former 

 will also stand exposure, 1 ut as a rule thrives better if the shade 

 is fairly dense. The glandular character of the indusium of this 

 fern varies with the environment. These ferns also thrive well 

 in clay loam, especially on the face of slopes. In this location 

 they are shaded by hard maple, beech and ironwood, with cedars 

 and an occasional hemlock. 



Aspidium cristatum (L.) Sw. (Crested Shield Fern). This 

 fern prefers a mucky soil; its locations overlap those of Aspidium 

 Thelypteris and Onoclea. Trees peculiar to such a situation, 

 such as ash, cedar and mountain maple furnish the necessary 

 shade. In comparison with its associates, however, it appears 

 always to select a somewhat higher station and is found growing 

 on logs and around stumps. It stands exposure fairly well ; 

 this may be due to the fact that the sun exercises a directive 

 influence on the position of the pinnae. 



Polystichum acrostichoides (Michx.) Schott. (Christina s 

 Fern), and Adiantum pedatum L. (Maidenhair). These ferns 

 are both very sensitive to exposure and are found only where 

 the shade is very dense. Their habitat seldom overlaps with 

 Aspidium spinulosum and A. marginale in their cedar swamp 

 location, but often does in the hardwood station. Thus on a slope 

 where the humus overlies a clay loam the four ferns mav often 

 be found. A dense shade is produced in a typical location by 

 maple and beech, while an occasional hemlock and basswood 

 may also be present. In such a habitat, P. acrostichoides 

 will almost invariably be found towards the top of the slope, 

 while A. pedatum selects the rather more moist and sheltered 

 location at the foot. 



Asplenium Filix-femina (L.) Bernh, (Lady Fern). This 

 fern is found at its best when growing at the edge of a mucky soil 

 location. Under these circumstances it will be shaded by cedais 

 and hemlocks, but trees peculiar to the transition zone, such as 

 birch, soft elm and basswood, will also be found. It stands 

 exposure to the sun very well. Sometimes it is found associated 

 with Aspidium cristatum, but, in general, it prefers a 

 habitat that is wetter. 



Asplenium angustifolium Michx. (Narrow-leaved Spleen- 

 wort). In a station examined in Peel Countv this fern was growing 



