—59— 



somewhat, are one or more slight tooth-like knobs on each edge. 

 As far as I know there is but one other species among our ferns 

 that has these peculiar outgrowths. The stem of this other spe- 

 cies, A. filix fcemina, might easily be mistaken for that of Dryop- 

 teris simulata were it not for this peculiarity. It is interesting 

 to notice that although in general appearance Asplenium angus- 

 tifolium and A. acrostichoides are so much alike, yet the former 

 has not the faintest trace, as far as I could see when making a 

 special examination with reference to this, of the little knobs. In 

 Gray's Manual, A filix-foemina and A. acrostichoides are put un- 

 der separate sections of the genus, the latter being placed next 

 to A. angustifolium. On the other hand, Prof. Underwood has 

 recognized the obvious relationship between the first two by 

 placing them together. As every detail of structure counts, why 

 should not the peculiarities of the stems above mentioned be cited 

 as arguments in favor of the latter's arrangement? It would 

 seem strange if such a deviation from the ordinary type of stem 

 should be found in but two of our ferns, and these two should be 

 only distantly connected. What is the purpose of these teeth ? — 

 C. E. Waters, Johns Hopkins University, Baltimore, Md. 



THE SENSITIVE FERN. 



JUST why that one of "our common ferns which bears the 

 coarsest foliage should be called the sensitive fern (Onoclea 

 sensibilis ), has never been quite apparent. One suggestion 

 is that it was because it withers so soon after being cut. Another 

 and more reasonable explanation' assigns the name to the plant 

 because it withers at the first hint of frost; but with even better 

 reason this name could be given to Pellaea Stelleri, whose fronds 

 are often gone by August. In an old book entitled " Conversa- 

 tions on Botany," another suggestion for the origin of the name 

 is given. It is to the effect that the fern will wither immediately 

 on being touched by the human hand, but withstands the touch 

 of other bodies. The German botanist, Sprengel, is quoted as 

 having proved the truth of this statement by numerous experi- 

 ments. In Rees' Cyclopedia it is stated that "the barren fronds 

 are smooth and of a thin texture, so delicate that, as we have 

 heard, the frond soon fades after being drawn through the hand 

 when growing." Doubtless these stories were made to fit the 

 name, rather than the name to fit the facts. One thing should 

 be remembered in reference to Onoclea sensibilis — it is a water- 



