76 ENGLISH BOTANY. 



viz., that we must consider L. cristata, L. uliginosa, and L. spinulosa 

 as one species. In the ' Phytologist ' for 1852, p. 694, Mr. Newman 

 states that " he had possessed for at least 6 years a plant of that form 

 of Lastrea usually known as cristata, but to which he wished to 

 restrict the name Callipteris, by Ehrhardt. This plant originally 

 came from Bawsey, and was most rigidly typical of its kind ; cultivated 

 in a dry London atmosphere, it had strictly retained its original 

 characters, except that, getting weaker year after year, it has grown 

 small by degrees and beautifully less. The weather at last proved 

 too dry, and this individual plant was planted in bog earth, abun- 

 dantly supplied with water and placed in a close greenhouse, where 

 the thermometer frequently rose above 90° Fahrenheit. Its growth 

 became vigorous in the extreme, but this was not all. Frond after frond 

 appeared, each receding more than the last from the typical figure of 

 Callipteris, and approaching that of uliginosa, and at the present 

 moment it has fronds evidently from the same cormus, which would 

 serve admirably as representatives of both supposed species." I have 

 tried treating L. cristata in this way for six years, but it has 

 retained its typical form. Mr. Newman says that in spring it is 

 20 days later than multiflora (dilatata) in expanding, 10 days 

 later than L. spinulosa, and from 10 to 15 days earlier than Callip- 

 teris (cristata), which accords pretty well with my own experience, 

 except that I find 10 instead of 20 days the difference between 

 dilatata and spinulosa ; but Mr. Moore has never found any constancy 

 in this respect with cultivated plants. The fronds of L. uliginosa 

 last till December in ordinary years. 



Milde quotes Aspidium Boottii, Tuckerman (A. spinulosum var. 

 Boottii, G-ray, Man. Bot. U. S.) as a synonym of L. uliginosa, and I 

 have characteristic specimens of it from Christiania, sent by the late 

 Professor Blyth, under the name " Polystichum spinulosum, var. fere 

 P. Boottii, Americanorum," but in Gray's Manual the involucre of 

 Boottii is said to be glandular, and the plant to be closely allied to the 

 European form A. remotum, Braun, while in Hook, and Bak. Syn. 

 Fil. it is referred to L. spinulosum, and L. collina, Newman, is given 

 as a synonym of var. Boottii. I have no specimens of it, and therefore 

 I have not ventured to quote the American name. 



Lloyd's Shield-fern. 



SPECIES VIII.-L ASTREA SPINULOSA. Presl. 



Plate 1855. 



Babenh. Crypt. Vase. Europ. Exsicc. No. 18. 



L. spinosa, Newm. Nat. Hist. Brit. Ferns, ed. ii. p. 209. 



L. cristata, var. spinulosa, Moore, Nat. Print. Brit. Ferns, 8vo. ed. Vol. I. p. 210. 



Nephrodium spinulosum, " Desv." Bool. fil. Stud. Fl. p. 466. 



N. spinulosum, a, Hook. & Bah Syn. Fil. ed. ii. p. 275. 



