540 VERNATION OF THE BRITISH FERNS., {^September, 



ences as to heat^ soil, etc. The fronds measured belong to well- 

 established, Avell-developed plants, and the border has been planted 

 three years. 



ft. in. in. 



Osmunda regalis . . in length 1 10 Polypodium cambricum, quite close. 



Polystichum aouleatum ... 7 Polypodium calcareum .... 8 



Polystichum angulare .... 8 Polypodium Dryopteiis .... 4 



Lastrea recurva 11 Polypodium Phegopteris .... 6 



Lastrea dilatata 1 11 Asplenium Trichomanes .... 2 



Lastrea colUna 12 Aspleuium Adian turn- nigrum . . 4 



Lastrea spinulosa 9 Scolopendrium vulgare .... 6 



Lastrea uliginosa 6 Cystopteris fi-agHis 8 



Lastrea eristata, quite close. Cystopteris dentata 4 



Lastrea cristata, North America 1 4 Pterisaquilina,just beginning to appear. 



Lastrea rigida 6 Athyrium Filis-fomina . . . _. 7 



Lastrea Oreopteris 6 Athyrium Fihx-foemina, var. crispa 4 



Lastrea Fdix-mas 16 Athyrium Filix-foemina, var. eristata 4 



Lastrea Fihx-mas Borreri, quite close. Athyi-ium Fihx-foemina, var. irriguum 4 



Lastrea Thelypteris .... 7 Blechnum boreale 2 



Polypodium vulgare, quite close. 



One of the most interesting facts to be deduced from the above 

 observations is the very regular manner in which the spinulous 

 section of the genus Lastrea rise with regard to each other, those 

 which have the most divided fronds appearing first, and those 

 with less divided ones following at regular intervals of about six 

 days, so that when L. eristata rises, it may be said to be a month 

 later than either L. dilatata or L. recurva. But what shall we 

 say to the L. eristata of North America, which is rather less 

 divided than our British species, yet is double its size, and is a 

 month earlier in its vernation ? This fact I can vouch for, hav- 

 ing grown the two together for several years. 



Another fact worthy of remark is the very great discrepancy 

 between the common form of L. Filix-mas and the variety or 

 species known as Borreri ; the former began to unroll its fronds 

 the last week in April, whilst the latter never exposed a single 

 pinna before the 1st of June. I have three fine plants of Bor- 

 reri and two of L. Filix-mas, all growing close together, and I 

 have observed for several years that the difference in the time of 

 vernation is a constant character. Other distinctions may be 

 pointed out, and though they are none of them very great ones, 

 they are all of them constant ones. To begin with them in their 

 wild state, L. Filix-mas affects shady lanes and the banks of 

 ditches, whilst Borreri is more frequently found upon a scrubby 



