279 



cieiit. The writer of this, furnished with a vast collec- 

 tion of Ferns in the LinnfEan herbarium, and from that 

 of Sir Joseph Banks, first suggested an additional prin- 

 ciple of arrangement, derived from the form and mser- 

 tion of the membranous cover, or involucnim, and espe- 

 cially from the direction in which that part bursts, or 

 separates from the frond, when arrived at maturity; 

 whether, if lateral, at the side towards the margin of the 

 frond, or of its segments, or towards the rib or yem ; or, 

 if terminal, towards the extremity, or contrariwise. This 

 principle is found to produce very certain distinctions, 

 and to establish the most natural genera. All subsequent 

 writers on Ferns have adopted it. First, Dr. Swartz, in 

 liis Synopsis Filicum, con^^iders the part in question as ot 

 eminent importance in defining the genera, and has es- 

 tablished several new ones on characters taken there- 

 from ; bestowing liberal commendation, in the 5th page 

 of his preHice, on his friend the inventor of this method. 

 Willdenow in his Species Plantarwn, vol. v., follows it 

 widiout a word of acknowledgement, as does Dr. Kurt 

 Sprengel in a rather superficial work, scarcely worthy of 

 its able author, translated into English by Mr. Konig, 

 under the title of An Introduction to the Study of Crypto- 

 iramous Plants, 1807; the fiirures of which are quoted in 

 the following pages, and will be found very useful in tlie 

 illustration of other vegetables of this class. But what- 

 ever deficiency of candour or knowledge may ex'st in 

 other writers, Mr. Brown, in establishing the curioiis 

 genus JVoodsia, has done ample justice to his inend s 

 claims, which no one was more competent to appreciate. 

 See Tra?is, of Li mi. Soc. t;. 11. 170. 

 The roots of Dorsiferous Ferns are perennial, either tube- 

 rous or creeping, scaly, often parasitical, with crooked 

 stout radicles. Plants mostly herbaceous, natives ol .shady 

 or damp situations, in almost all climates, cither ever- 

 jrreen or deciduous; those of tropical countries some- 

 times arborescent, and occasionally spinous; \he pubes- 

 cence oWiW, in general, scaly rather than hairy. LrcnuhsMh 

 a simple or alternately branching stalk; the leaf either 

 firm or more rarely membranous, ribbed, veiny, jialest 

 in some degree at the back ; either simple or variously 

 i)iunate; undivided, pinnatifid, or lobed ; the dmsmns 

 inostly alternate ; entire or serrated ; bearing the/r//r//- 

 /ication at the buck, verv seldom at the edges, as above 



