Spinulose Fern 127 



Habitat. Woods, dry or damp, swamps, stone-walls, and 

 shaded hillsides. Often on crumbling logs or beneath ever- 

 greens. 



Range. Labrador to Alaska, south to North Carolina and 

 Tennessee. 



Dryopteris spinulosa intermedia (Muhlenberg) . Underwqod, "Our Na- 

 tive Ferns," ed. 4. 116. 1893. 



A spi diu m intermedium Muhlenberg. Willdenow, Sp. PL, 5: 262. 1810. 



Dryopteris intermedia. A. Gray, Manual, ed. i. 630. 1848. 



Aspidium spinulosum var. intermedium. D. C. Eaton in A. Gray, Man- 

 ual, ed. 5. 665. 1867. 



Nephrodium spinulosum var. intermedium. Davenport, Rhodora, 4: 53. 

 1902. 



YOUNG plants of Dryopteris spinulosa intermedia are often to 

 be seen on old logs and stumps in wet woodlands. 



The leaf is often deltoid at an early stage of develop- 

 ment, but usually changes in shape later; in what way can be 

 seen from Pis. XXXIII-XXXV. 



The venation is pinnate. With rare exceptions each tooth 

 or simple lobe of the leaf- blade contains a veinlet. For instance : 

 in a leaf-blade consisting of two simple lobes, such as PL XXXIII, 

 Fig. i, represents, the primary midvein of the blade does not ex- 

 tend beyond two simple basal primary branches, each of which 

 occupies one of the lobes: in a blade consisting of three simple 

 lobes, a simple veinlet from its midvein occupies each of the lobes : 

 if a lobe is two-toothed, which is often the case in different stages 

 of the leaf's development, the vein belonging to that lobe has 

 two simple branches, each of which occupies one of the teeth. 



It cannot be said, however, that with rare exceptions each 

 veinlet of the leaf-blade ends within a tooth or simple lobe. For 

 instance, in the mature leaves the incisions, by means of which 



