PTERIS. 155 



Willdenow. Pellcea (or AUosnrm) is tlic only group excluded, and I am far from 

 being convinced that that is a correct measure, and that it should not form rather 

 a section or subgenus of Pteris, with which many of its species are so closely 

 allied by nature and the general essential characters. 



It may be worth while to examine a little into the supposed advantages or dis- 

 advantages to be derived from the changes that have taken place in the genus 

 Pteris, since the days of Willdenow. 



Bernhardi was the first (in 1806) to propose the separation of Allosorus from 

 Pteris ; and if by his saying it was intended to include (besides Cheilanthes fra- 

 grans and Pteris crispa) " all the Adianta spuria " of Swartz, he meant Swartz's 

 second group or section of Pteris, " Adiantoidea;," which comprises all Swartz's 

 species of the genus Pteris, which had the " stipes fuscus Adianti," irrespective 

 of any other character. Gaudichaud's characters for dividing Pteris into sec- 

 tions, given in Freycinet's Voyage, are too vague to merit much attention, and no 

 one seems to have followed up Bernhardi's views till Mr. Brown's valuable dis- 

 quisitions on the " Modifications of vascular structure, or the various ramifications 

 of the bundles of vessels or veins of the frond, combined with the relation of the 

 sori to their trunks or branches, as the most advantageous source of character for 

 subdivision, not in Polypodium only, but in other extensive genera of Ferns,"* 

 appeared first in the ' Prodromus Fl. Nov. HoUandia;' (1810), then in Dr. Wal- 

 lich's ' Plantae Asiaticae Ilariores' (1830), and the subject was more fully discussed, 

 at a later period, in the ' Flora Javae ' (1838). These induced Dr. and Professor 

 Presl, in his ' Tentamen Pteridographiae, sen Genera Filicacearum prssertim juxta 

 venarum decursum et distributioneni exposita,' 18, to give a degree of importance 

 in the formation of genera far beyond the views of the illustrious author just 

 mentioned, and to separate from the genus Pteris of the older authors, besides 

 Allosorus (which he makes to include several species), Cheilanthes, Onychium, 

 Pteris aquilina, and its allies, IIaplopteris,f (Pteris scolopendrina, Bory), Mono- 

 gonia (since abolished), characterized by the lowest opposite veins uniting in an 

 acute angle at the apex, Campteria, Litobrochia, and Amphiblestera (already no- 

 ticed). This work is rendered the more valuable from the number of figures 

 illustrative of his views, in general faithfully, if not artistically, executed. This 

 multiplication of the genera of Ferns, upon what we conceive to be slight grounds, 

 is carried out to a still greater extent in the same author's ' Epimelia; Botanicae,' 

 1849; but no change is there attempted among the P/eriV/ece. The excellent 

 Agardh (Recens. Sp. Pteridis, 1839) excludes the Allosori of Bernliardi and Presl, 

 but otherwise preserves the Linna^an genus Pteris, and makes an excellent use of 

 the venation, as of great importance for characters of the subdivisions. 



Link (in 1841) took a more correct view oi Allosoi'us, by confining it to the 

 Pteris (Cryptogramme, Dr.) crispa, in which he has been followed by many 

 others. He constituted the genus Pellcea, referring to it a tolerably natural group 

 of old Allosorus, in which, as explained at p. 131, we liave followed him. lie 



* Brown, under the description of Polypodium (Dipteris) Horsfieldii, in ' Flora 

 Javae,' p. 3. 



t Fee places Presl's Haplopteris amongst the " Incerta Genera." Moore (In- 

 dex Filicum, p. xli.) places it next to Pteris, and on the authority of original spe- 

 cimens in Herb. Reward, describes the indusium as truly pteroid. I have every 

 reason to believe that the Fern on which 1 founded my genus Tteniopfcris (Gen. 

 Fil. t. LXXVI. B), T. Forbesii, from the Mozambique coast, a Vittaroid Fern, is 

 identical with it; and there the sori are so sunk, and the edges or margins so 

 dilated, that they may easily be taken for a douljle involucre ; in some cases even 

 the sorus in age conceals the inner of these two supposed involucres, and then 

 the outer one resembles that of a Pteris ; hence Presl's Haplopteris, a name, if 

 the genus were a valid one, is to be preferred to Tceniopteris or to Tceniopsis of 

 J. Sm., which is identical with it, and of earlier date. 



