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A fern stem is not merely a round stick, without individuality. 

 If one cuts across it with a sharp knife, one or more light dots or 

 lines will be seen near its center. These are the cut ends of the 

 fibrovascular bundles. They serve as the main arteries of the 

 plant, and at the same time give it strength and firmness. If we 

 crush an Osmunda or other succulent stem, we can pull out these 

 'fibres in long pieces and test their strength with results that will 

 probably surprise us. That the fibrovascular bundles are arranged 

 so as to give the greatest strength to the stem i3 admirably shown 

 in such species as Dryopteris acrostichoides and D. marginalis, 

 where the two largest bundles are at the front or upper side of the 

 stem, so that when the frond curves over naturally, these strong 

 fibres are on the convex side, and thus prevent bending too far. 



Many ferns, even those not growing on rocks and therefore 

 not needing scaly fronds as a protection against drought, have 

 very scaly stems. During the winter these scales serve to protect 

 the young fronds, not from freezing, as is often stated, but from 

 sudden alternations of cold and heat. In the case of the mature 

 fronds, extended observations would be necessary to decide 

 whether the scales protect the fruit dots from the attacks of 

 insects that must creep up the stem. It is well known that hairs, 

 etc., on the stems of flowering plants often prevent the removal 

 of the pollen by improper insects. 



The questions of specific differences and group resemblances 

 are most interesting ones. Many stems can be recognized at a 

 glance — for instance that of Onoclea Struthiopteris with its V- 

 shaped cross-section. An Osmunda stem is recognized by its 

 curiously rolled up fibrovascular bundle. That of the cinnamon 

 fern differs from that of O. Claytoniana chiefly in lacking two 

 slight lateral ridges. The stems of Asplenium Filix-f amino, and 

 A. acrostichoides differ from others in having on each side near 

 the rhizome several tooth like projections. Some botanists place 

 these two species under separate sections of the genus. These 

 peculiarities do not tend to strengthen this position. They are 

 wanting in A. angustifolium. 



Asplenium platyneuron, A. Bradleyi and A. jnontanum 

 form an interesting series. Bradleyi is clearly intermediate be- 

 tween the other species as far as its texture, shape of pinnae, etc., 

 are concerned, and Prof. Eaton went so far as to say that if there 

 were a hybrid between piatyneuron and montanum, it would 

 very closely resemble Bradleyi. Of course it is not considered a 



