BOTANICAL GAZETTE. 81 



the plant when growing. I have observed the same plieuoniena, and apparently from 

 the same cause, iu other species, but it sometimes occurs when the plant has not received 

 any injury. I have a specimen of B. Virgiuianuin with two ])erfect fertile spikes, the 

 common stalk forking just above the union with the sterile frond. Tlie tendency to 

 fork on the part of our ferns I have found toljc quite common. I have noticed and re- 

 ceived from correspondents, numerous specimens of tiie dift'erent genera and species. 

 Some curious examples occur in CmnptoHoran, some specimens forking directly from 

 the simply auricled base, making a double frond, and others forking from the long- 

 attenuated tips. 



In Dicksom'a I have obsei-ved specimens iu which not only the frond l)ut the piunse 

 also were forked. — Geo. E. Davenport. 



AspiDiuM .spiNULOsu.M, Swz. — ^Wliat makesvarieties? I do not know that I clearly 

 apprehend the meaning of your correspondent who imthe Nov. number inquires if his 

 specimen of this species may not be "another of the many plants where the so-called 

 'varieties' are merely forms with individual instead of local peculiarities," but I have 

 always supposed that it was individual peculiarities that made varieties. A plant that 

 depended altogether upon local influences for its character would be very apt to run 

 back into tlie normal form of the species on being removed from those local influences 

 and such a plant I should not consider as a variety at all. If itbe local pecularities that 

 make varieties then how does it happen that all of the plants growing within the ranges of 

 the same local influences are not always of the same character V Within an area containing 

 at least half an acre of Aspidiuw. spinulosuin, in the vicinity of Boston, I find many 

 forms of i^pinnlosuiii all growing together and subject to the same local influences, and 

 I fail to see how two plants of one species growing side by side, under precisely the 

 same influences, can liave two distinct forms if it is local influences alone that make 

 their peculiarities. Rather I should say that these peculiarities came from some cause 

 inherent in the plants themselves and that, therefore, it is individual and not local 

 peculiarities that make varieties. — Geo. E. Davkxport. 



Pyrus Americana, DC. — This beautiful tree makes its home in central Pennsyl- 

 vania near the sumit of the mountains, marking with uniformity a line of about 1,800 to 

 1,400 feet above tide. As you climb the steep ascent of Tussey and Bald Eagle moun- 

 tains, among masses of broken rocks covered with lichens, a trio of beautiful small 

 trees attracts your attention — Pynis Americana, DC, Betuhi papyraceK, Ait., with its 

 white bark and graceful spray, and Acer Pennsylcdnicnm. These all seem to love a 

 lofty exposure, and thrive on the scanty debris of shattered rocks. Acer Pemuyhaniewn 

 is often met with at lower elevations. Ascend either of these mountains in tlieir trend 

 to tlie north east through Huntingdon and C'entre counties, j'our ai)proach to their sum- 

 mit is heralded by clumps of the Bircii and Pyrit.-^ AnteriraiKi. There is, however, a 

 marked exception to this habitat of high exposure. The Pyru-^i Aiiwriainti makes a 

 sudden descent of about 700 feet to the base of Tussey Mountain. Two miles east of 

 Spruce Creek Station on the Pennsylvania Rail Road a small colony of a dozen bushes, 

 dwarfed to six feet in height, is found growing over an area of a half acre of rocks. The 

 reason for this departure from the usual elevation of the tree is found in the fact that 

 below these rocks perpetual ice creates a cold atiuospherc. This intei'csting locality, 

 sheltered from the direct action of the sun by the precipitous mountain side and the 

 erosion in it made by water action in an earlier era, has the cool, dami) atmosphere of 

 ice in the warm days of August. The ice is concealed by rocks covered with a vigorous 

 growth of mosses, shrubs and trees, and is found [in August] sonic three feet Ijelow the 

 surface. 



In the same locality grows PimiH iSfrohi/.s, L.. .lA/r.v ('atKitli'iisix. ]\Iichx., Miichelld 

 repen.H,Ij., Muhus iitrigoim.i, Miclix., Frayaria rcunt, j^., liihix jirostnitnin. L'llcr., Ilfin-li- 

 fra puhescenx, Pursh. — J. R. L. 



