THE MALE FERN DRTOPTERIS FILIX-MAS 



the base of the pinna rachises near where these join the main rachis. This character 

 was first pointed out by Newman, and I have also found it very rehable even in hybrids 

 with D. Filix-mas. 



(8) The spores are consistently larger than in either of the other species, though some- 

 times much admixed with abortives for reasons which will appear. Figures will be 

 found in Chapter 1 1. As a rule only 8 spore mother cells instead of i6 are produced in 

 one sporangium. 



(9) Prothalli consistently apogamous (cf. Fig. 42 a, d). 



(10) Habitat closely resembling D. Filix-mas, though with local strains accompanying 



Fig. 40. Spores o{ Dryopteris abbreviata Newm. x 100. 



Fig. 



4 1 . Spores of diploid Dryopteris 

 Borreri Newm. x 100. 



D. abbreviata. Common all over Great Britain, often forming almost pure stands covering 

 large areas. In these cases the appearance of a local population is very uniform, and the 

 feeling of individual differences so easily detected in D. Filix-mas is quite absent. Popula- 

 tions characteristic of different localities may show differences of detail (see below). 



The history of Z). Borreri, like that of Z). abbreviata, is a record of a centiu^y or more of 

 dispute. Many synonyms were already pointed out by Newman in 1854, the plant 

 having been generally recognized both in Great Britain and on the Continent as a 

 very distinct 'variety' (cf Babington's Manual of British Botany). Its claim to specific 

 rank has been repeatedly made, notably by Wollaston, who proposed the name ofLastrea 

 pseudo-mas for it in 1855. This name is illegitimate, but as an index of the amount of 

 attention that the idea of the species has received from continental botanists (unlike 

 Dryopteris abbreviata) it may not be without interest to append a translation of a short 

 note which appeared in the Proceedings of the Swiss Natural History Society, published in 

 Geneva in 1937 {Verh. schweiz- naturf Ges. 1937, p. 153): 



'THE RANGE OF FORM IN DRTOPTERIS BORRERI NEY^M.' 



By Franz von Tavel (Bern) 



'The author, in collaboration with E. Oberholzer of Ziirich, has attempted to sum- 

 marize the wealth of forms within Dryopteris Borreri, a group of ferns which is generally 

 included in floras under the now obsolete names of Z). Filix-mas var. paleacea (Moore) 

 Druce, and var. subintegra (Doll) Briquet. The results are as follows: 



I. D. Borreri Newm. s.str. Indusium stiff, leathery, turned inwards at the edge, 

 sometimes splitting in a few sori. 



55 



