302 ON THE EUROPEAN SPECIES OF FESTUCA. 



in Italia et Tyrolia collectsB,' t. xii., f. 1.— Species new to Britain. 

 Minety, Wilts. 



Spirotcenia ohscura, Ralfs. — Penzance ; sparingly. Not before 

 recorded. 



In some Algae received from Mr. A. W. Wills, from Capel 

 Curig, N. Wales, the zygospores of Zanthidium armatum were 

 abundant. 



The following, collected at Slewdrum Bog, Aberdeenshire, I 

 received through the kindness of my friend Mr. J. Roy. 



Didymoprium, Borreri, Ralfs. 



Gonatozyyon Ealfsii, De Bary. 



Euastnim pectiiiatum, Breb. 



ON THE EUROPEAN SPECIES OF FESTUCA^ 

 By F. Townsend, M.A., F.L.S. 



(Concluded from p. 281.) 



B. — Of Degree (Grad) in Species-making, Variation, Culture, 

 Hybrids, Systematic Arrangement, and Nomenclature. 



Prof. Hackel describes how, whilst pursuing his study of the 

 genus Festuca, he came by degrees to the conclusion that Jordanic 

 species have no existence in Nature, but that such species consist 

 of groups of individuals which resemble each other more closely 

 than those of another immediately-aUied group. Nor does he 

 believe in the existence of an absolute species, but considers that 

 the word must always have a relative signification. He describes 

 how he saw three ways open to him — 1st, to look upon all dis- 

 tinguishable and recognisable forms as species, and to collect the 

 minor si)ecies into groups which should be equal in rank to the 

 more distinct and isolated species ; 2ndly, to look upon all forms 

 as species, but to divide them into species of 1st, 2nd, 3rd, and 4th 

 rank, as Focke has done with the Fiuhi, in which case the word 

 species must cease to express a logical meaning ; or 3rdly, and this 

 course the Professor decided on adopting, to consider as species 

 those groups of forms which are homogeneous and are separated 

 from the nearest allied forms by several constant characters ; and then, 

 out of the numberless slightly differing forms, to constitute groups 

 or collective species, the difference between these being much greater 

 than that between the single members of the group, provided that 

 extremes be not chosen. In this way the number of species is 

 much reduced ; some are homogeneous, others are heterogeneous, 

 and it becomes necessary to introduce the ranks of subspecies, 

 varieties, and subvarieties. 



Prof. Hackel' s idea of a species may be gathered from the 



* [Mr. Townsend has requested me to say that his own heading to this 

 article was 'On Prof. Hackel's Monograph of European Fescues' — a title which 

 he considers more appropriate. — Ed. Jo urn. Box.] 



