972 



scarcely differing from tbein at the two extremes, or from each other 

 in their intermediate links. I have paid considerable attention to P. 

 aculeatum and its supposed varieties for upwards of ten years ; and I 

 now believe that the plant has no constant variety whatever. 



" In the month of May, 1842, I took up a plant of this species in 

 the neighbourhood of Egham. It had fronds about a foot long, 

 and was a good representation of what botanists call var. lohatum. 

 This was planted in a bed of bog-soil, which had been purposely pre- 

 pared for ferns, in a rather exposed situation. It kept its character 

 (or, rather, retrograded) for three years. In 1845, the whole of the 

 ferns in this bed were removed to another place, where the natural 

 soil was light, the subsoil gravel, and the situation shady. Here our 

 plant soon found itself at home, and in three years attained as high a 

 state of development as I have ever observed in any plant of this spe- 

 cies ; it then became stationary, and remains so up to the present 

 time. I have now before me a frond of it, of last year's growth, nearly 

 three feet long by somewhat more than six inches broad. The pin- 

 nules are distinctly stalked for more than two-thirds of the length of 

 the pinnae. In this state, it comes near to P. angulare, but differs 

 from that species in its more rigid texture, narrower outline of frond, 

 more crowded pinnae, more acute, strictly serrate pinnules, and in its 

 never becoming subtripinnate, which fronds of P. angulare, of two 

 feet long or more, invariably do. I have observed another difference 

 between these plants, which (to the best of my knowledge) has not 

 been recorded by any botanist. P. angulare is very proliferous, pro- 

 ducing lateral crowns freely ; whereas P. aculeatum never does, except 

 when its crown gets destroyed by accident, and then it will. In the 

 spring of 1852, I took up a plant with four crowns, in various stages 

 of development, from lonchitidioides to lobatum. Near as these two 

 species are to each other, there are two acknowledged species between 

 them, or, rather, placed opposite to their point of junction ; I mean 

 P. pungens and P. proliferum. Both are as rigid as P. Lonchitis ; 

 and whilst the former has the broad, subtripinnate frond of P. angu- 

 lare, the latter has the narrower frond and decurrent lobes of P. acu- 

 leatum ; it is, also, viviparous near the apex of the frond, but not 

 constantly so. 



" Nine years since, I collected about a dozen plants upon a dry 

 bank. They could scarcely be called more than pinnate ; and I 

 thought I had got var. lonchitidioides. One of these I potted, and 

 kept in a greenhouse ; and in three years it came to the same state 

 of development as the plant first mentioned was when I first saw it. 



