50 



find it not twice pinnate and fully three times so, with fruit scarcely 

 visible, and dots so large as to be plainly seen at quite a distance. 

 Sometimes the lower pinnag are much reduced, sometimes very much 

 extended. To take prominent varieties one would at a glance pro- 

 nounce them very different species, so much more do they vary in 

 appearance than many species which are distinct; but I can show a 

 suite of specimens which run so gradually from one to another that 

 it will at once be seen that to draw a separating line would be quite 

 impossible, and the best that can be done is to name the prominent 

 forms as varieties. The typical plant is rare and as yet I have only 

 found it at Essex. Doubtless other localities will be discovered. 



19. Var. intermedium. The common form will be found in nearly 

 every patch of woods. 



20. Var. dilatatum is a larger and more cut form, most common at 

 the mountain regions of New Hampshire. A near approach to it can 

 be obtained at Essex, Beverly, Georgetown (Mrs. Horner), etc. 



21. Var. Boottii is much mox-e narrow, reduced at the base. This, 

 to judge from the specimens I And, which are very numerous, seems 

 to resemble much more closely A. cristatum than A. spinulosum. The 

 sterile fronds particularly resemble each other in these two species 

 and it is often very difficult to decide to which they belong. Is it 

 possible that this can be a hybrid between A. spinulosum and A. cris- 

 tatum? Found in shady, swampy land. 



22. AspiDiuM CRISTATUM Swartz. 



Crested Buclder Fern. 



Not so common as some varieties of the last. It grows in similar 

 localities, but seldom more than one or two clumps in a place together. 

 The fertile fronds are usually much taller than the sterile and perish 

 during the winter, while the sterile ones of the previous year are 

 found quite perfect the next spring. 



Found in nearly every town in localities similar to the last. 



23. AspiDiuM MARGiXALE Swartz. 

 Ilarginal or Evergreen Wood Fern. 



(So called as the fruit is close to the edge or margin of the pinnule, 

 and the fronds are often found as perfect in spring as they were before 

 winter came.) 



This fern is of a beautiful blue-green and is found in rocky vpoods, 

 where the foliage is not thickest. The fronds are twice pinnate and 

 occsisionally found still more cut. Eight years since I collected in 

 Swampscott a plant with very broad and much cut fronds. This I 



