PKLLiEA. 131 



or flexuous rachis mostly eheiieous, glabrous and glossy, or 

 more or less clothed ivith chaffy hairs or scales. 



The Ferns which I now bring under the genus Pellcea of Link, I liave been 

 accustomed, in my miscellaneous writings on Ferns, to refer to AUosorus, a genus 

 suggested by Bernhardi, maintained and greatly extended by I'resl, and more 

 satisfactorily circumscribed by Kunze. But it must be acknowledged to have 

 undergone so many changes and rejections that I am not sure if Bernhardi would 

 acknowledge any of the species now generally referred to it, as belonging to his 

 genus JUosorus. We have elsewhere, in discussing the genus Crypt ogrannne of 

 Brown, quoted Bernhardi's definition of Allosorus, and that author further re- 

 marks (' Neues Journal fiir die Botanik,' vol. i. part 2, p. 3G), " The genus Allo- 

 sorus includes all the AJinnIa spuria of Swartz, besides Adiantum pusillum, 

 Willd. (Pteris acrosticha of B/il/ns, — Cheilanthes fragrans of this volume, p. 81), 

 "Pteris crispa, and probalily hoterophylla, Sw. 1 have given it the name in con- 

 sequence of the diversity in the grouping of the sporangia " (thus those who 

 alter the name to Allosurus do so in error). " In some they are mostly solitary, 

 as in Allosorus pusillics, in others they are clustered. In some there is only one 

 to each hyposporangium, in others several." — Now as Swartz has no group or 

 division of "Adianta spuria," it may admit of doubt as to what is here meant by 

 the term, and Fern writers seem to consider it to mean species ef Cheilanthes. 

 One thing is certain, that the Linna^an Pteris crispa is not mentioned as if it 

 were considered the type of the genus; and we cannot but think that so ill-de- 

 fined a genus as this of Bernhardi, is better abolished. And such seems to be 

 the opinion of others, or they only maintain it for Pteris crispa. Professor Link,* 

 in 1841, established the genus Pell(pa,f or the legitimate species of Allosorus 

 of Presl and Kinize, and Mr. J. Smith.t in 1842, published his genus Platyloma, 

 and transfers the Allosori just mentioned, in part at least, to that genus, and the 

 rest to Cassebeera of Kaulfuss. In tine, M. Foe, in his elaborate ' Genera Fili- 

 cum,' gives the preference to Pellcea, and we gladly follow him. 



If we consider the fructification, the difference between Pteris and Pellcea is 

 this ; that whereas in the former the sori arise from a longitudinal continuous re- 

 ceptacle in the axis of the involucre, in Pellcea the sori are in reality separate, 

 having their origin on the apex of the veins, more or less covered when young 

 by the involucre, but eventually becoming confluent, so as to form apparently a 

 continuous marginal sorus. It is true this is too often a microscopical character, 

 which few are able to avail themselves of; but happily there is a habit which, in 

 many Cryptogamic plants, comes to our aid as a secondary character of great im- 

 portance. " On les reconnait " (the species of Pellcea, says M. Fee), " a la pre- 

 miere vue a I'epaisseur des lames, souvent opaques et a la couleur verte olivatre 

 qu'elles prennent en se dessechant. Les stipes et les nervnres principales ont 

 cette consistance crustacee fragile et cette couleur noire luisante, si remarquable 

 dans les Adiantum. EUes ne produisent que bien rarement des ecailles frondu- 

 laires, et leurs dernieres divisions tendent a la forme lineaire, ou se terminent en 

 pointe." Still it must be confessed that many of these marks are inconstant, and 



* ' Filicum Species in Ilorto Regio Berolinensi cultse.' 



t From ire\os vel irfWos, niger, fuscus, " stipes rigidus, badius, unde PellKam 

 dixi" (Link). It is a little unfortunate that there should have been many years 

 earlier (1818) a Pellia, named in honour of a learned Florentine Advocate, Pelli, 

 given to the Epiphyllous group of Jungermannia among HepaticcP: a genus how- 

 ever, if known to Link, probably not adopted, even at the time his Pellcpa was 

 enounced : for Endlicher, in his ' Genera Plantarum,' published 1836-1840, refers 

 to it as not generally received. 



t In Hook. Bot. Journal, vol. iv. p. 159 and 160. 



