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A NEW BRITISH MOSS (FISSIDENS ALGARVICUS Solms). 



By H. N. Dixon, M.A., F.L.S. 



In 1868 Graf za Solms-Laubach described a new species of 

 Fissidens gathered by himself two years earlier near Silves, a town 

 of Algarvia, in the south of Portugal, under the name of F. algar- 

 vicus. Its specific rank is maintained by Schimper in the second 

 edition of his Synopsis, and by most recent writers, but some subse- 

 quent authors have referred it as a variety severally to F. pusHltis 

 Wils. (Boulay) and F. incurvus Starke (Husnot). Mitten ( Journ. 

 Linn. Soc, Botany, xxi. 555), referring it to F. viridulm Hedw., 

 states that it is the same as F. intralimbatus Buthe, but gives no 

 reasons for that assertion. (He refers to it as M F. introlimhatus 

 Buthe, Hedwigia, 1870, re-described by Schimper as F. algarvicus 

 C de Solms; but there are no specimens so named in his her- 

 barium, M apparently overlooking the fact that F. algarvicus was 

 originally described by Solms-Laubach himself two years prior to 

 Buthe's publication of F. introlimbatus.) F. Sardagnai Vent. (Bev. 

 Bry. 1883, 93) is also compared by its author with F. algarvicus, 

 which, however, he considers clearly distinct. Finally, Limpricht 

 (Laubmoose . . . iii. 671) says of F. Orrii (Lindb.) Braithw. (re- 

 ferred already by Mitten to his F. tequendamensis) , fl Vielleicht 

 identisch mit F. algarvicus Solms." 



One need have a pretty taste in Gordian knots to attack such a 

 problem spontaneously, and for my part its solution might well 

 have been left to our continental confreres in bryology, but for the 

 recent discovery of F. algarvicus in Britain. Early this spring Mr. 

 G. B. Savery sent me a few interesting mosses gathered by himself 

 and his brother near Exeter, and among them was a small Fissidens 

 growing on the red sandy shale of that neighbourhood, queried as 

 F. jnisiilus. A careful examination showed that it was certainly 

 F. algarvicus Solms, of which I possessed the specimen from Cher- 

 bourg, leg. Corbiere, issued in the Musci Gallia, No. 812; and I 

 was subsequently able to compare it with an authentic specimen 

 in the British Museum Herbarium from Solms-Laubach himself 

 au extremely meagre specimen, but sufficient to confirm the identity 

 of our British plant, and rather curiously growing upon a similar 

 deep red clayey soil. The question then arose as to the true 

 position and relationships of F. algarvicus, as to which I must 

 confine myself to a brief statement of the conclusions I have 

 arrived at, without attempting to justify them with any degree of 



completeness. 



F. algarvicus is, I am convinced, a good species, quite distinct 



from either F. viridulm, F. incurvus, or F. pusillus. The most 



obvious character, distinguishing it indeed from all our smaller 



species of Fissidens, is the gradually tapering, acuminate leaf-points. 



Other species, e. g. F. pusilius, often show a gradual narrowing of 



the leaves in the upper part, but the actual apex is always more or 



less abruptly pointed, or even subobtuse and apiculate ; in F. 



algarvicus it tapers gradually to an acute acumen, giving a very 



