FERN GROWING 171 



perfectly sterile (the variety is known as crispum-Cowburni). 

 Advantage has been taken of this rare chance to sow a number 

 of pans with the spores. 



Some very beautiful varieties are sterile, and amongst these 

 are Aspidium aculeatum var. piilcherrimum ; A. angulare var. 

 plumosum-grande (raised by Mr. E. F. Fox) ; A. angulare, var. 

 Pateyi; A. angulare var. plumosum (Moore) ; the three forms 

 of A. angulare, known as denstim, robustum, and laxum, in the 

 section phimoso-divisilobum ; Nephrodium paleaceum var. ramo- 

 sisstmum ; Polypodium vulgare var. cambruum ; Pteris aquilina 

 \2X. grandtceps ; Asplenium Trichomanes vax. incisum-Claphami 

 (and several others of the incisums) ; Asplenium marimim vars. 

 plumosum (Wollaston), Thompsonce, and mitltipinnatum ; Asple- 

 nium Filix-fcemina vars. Axminsterense , Barnesii, Clarissima, 

 Kalothrix, plumosuin, Willsii, and crispum. There are more 

 that might be enumerated, but the above are some of the most 

 beautiful of the British Ferns. The second class of sterile Ferns 

 which have sori, but have no perfect spores, are hybrids, having 

 only the rudiment of fertility without being fertile ; we may 

 instance Nephrodium, remotum, Aspidium hybridum, Asplenium 

 microdon, Asplenium. adiilterum, and a hybrid between Asple- 

 nium Trichomanes and Asplenium ruta-muraria which has 

 been found by Mr. G. B. Wollaston. 



Sterile Ferns can only be increased by division or by the 

 formation of bulbils, and this in either case is a very slow 

 process with most of them ; they are some years before they 

 throw up a second crown, and very few form bulbils. On the 

 other hand, any one who will devote time and attention to the 

 precautions that are set forth in raising Ferns from spores, can 

 in five or six years form a large and interesting collection of 

 Ferns which will teem with new varieties. There may be some 

 failures, but experience will surmount all the difficulties, and 

 the interest in watching the growth and development of the 

 seedlings is the reward of this diligence. 



