merely determine a deeper cut, and hence not only are no 

 spores produced, but the energy, which their production 

 would have absorbed, is free to be devoted to forming and 

 feeding a leafier development. A proof that this is, so to 

 speak, the modus operandi is seen in the plumose or crispum 

 Hartstongues. The true thoroughbred crispum is as 

 barren as P. v. cambvicuni, and as a result forms a deeply 

 and regularly frilled frond, but there are some crispums 

 termed fertile ones, in which irregular patches of spores 

 are produced, and it invariably happens that where the 

 spores appear on the frond back, the development of the 

 frill is affected, and the edges, instead of being regular, are 

 irregular and crenate. The veins in short cannot perform 

 both functions completely, and the one must be at the 

 expense of the other. As compared with the cristate varia- 

 tions, the plumose ones, especially the true plumosums, i.e. 

 perfectly barren ones, are very rare. In the Poly podium 

 family, besides P. v. camhriciim, of which, by the way, there 

 are several distinct forms besides the old one, viz. Bavrowi^ 

 Hadivinii, and last, but best, Prestonii, we have Phlehodiiim 

 {Polypodiiim) aureum Mayii, which originated in Mr. H. B. 

 May's Nursery at Edmonton, and P. (?) Knightii, an exact 

 reproduction of the Cambricum form in a very large grow- 

 ing exotic species, unfortunately not specified in the name 

 given. 



In the Lastreas we have several plumose forms of 

 L. montana, but none of the other species except L. /. ;;;. 

 BoUandae, an imperfect form. In the Asplenium family we 

 have A. triclwmanes incisnm, found several times, perfectly 

 barren and imitating P. v. camhvicum as much as a small 

 growing Spleenwort can. In the Nephrolepis we have 

 N. vufesccns tvipinnatifida, another sport on the same lines 

 of extra leafiness and barrenness. That magnificent 

 Maidenhair Ad. Farley ense is a thoroughbred plumose 

 form of Ad. scutum, as we once saw a specimen shewing 

 reversion to that species in several fronds. Taking 

 perfect barrenness as a feature, these are all the true 



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