42 



THE AMERICAN BOTANIST 



bracken, these are the only common ferns with triangular 

 blades. To be sure some of the Botrychiums have triangular 

 blades, but these are not regarded as true ferns and, in any 

 event, may be distinguished immediately by the fact that their 

 spore cases are borne in panicles and not on the under side of 

 the fronds. Should there be any question as to whether a given 

 species is a beech fern or a young bracken, the method of bear- 

 ing spore-cases will settle the matter, the bracken bearing its 

 spore-cases in a continuous line on the margin of the pinnules 

 instead of scattered on the veins at some distance from the 

 margin. 



To separate one species from the other is less easy; in 

 fact, the beginner is seldom sure which species he has collected 

 until he has a specimen of the other for comparison. Nature 

 seems to have been mindful of this confusion and has facili- 

 tated matters, somewhat, by giving each a slightly different 

 habitat. The broad beech fern (Phegopteris hexagonoptera) 

 usually inhabits dryish woods while the common beech fern 

 { Phegopteris polypoid ioides) , whose vernacular name is rather 

 a misnomer, is a lover of moist rocks and is usually tO' be found, 

 when it occurs at all, on dripping ledges and in the spray " of 

 waterfalls. The margins of the two habitats overlap some- 

 times, to be sure, but when one finds a beech fern in shady 

 woods it is a safe guess that it is liexagonopteva, while if his 

 specimen comes from wet rocks it is pretty surely poly- 

 podioides. 



A peculiarity of both beech ferns, but one that is most 

 noticeable in polypodioides, is the way in which the lowest pair 

 of pinnae are deflexed. They point downward and forward at 

 a rather sharp angle which gives them a very characteristic 

 appearance when gTowing". The common beech fern also 

 carries its blade at a considerable angle to the stripe. Growing 

 as it does on ledges and in clefts of rock the blades thus are 

 brought parallel to the face of the cliff and are doubtless borne 

 at the proper angle for securing the light. 



