472 SUMMARY OF CURRENT RESEARCHES RELATING TO 



scarce in Palaeozoic formations, we must not conclude that the hepatics 

 are therefore of comparatively late origin. They are almost as scarce in 

 the later formations. Their delicate leaves do not lend themselves to 

 preservation, and their elaters and other more durable structures are too 

 small to attract notice. The existing geographical distribution of the 

 hepatics is a line of research that would throw light on the degree of 

 antiquity of the group ; but it has not been much examined. The 

 spores are not suited for wide distribution, but usually require speedy 

 germination. After briefly surveying the distribution of other groups 

 of plants, the author treats that of hepatics in more detail, indicating 

 broadly the distribution of several genera of wide range. The obvious 

 conclusion from such a study of the hepatics is the small number of 

 genera and their wide distribution, especially in case of the genera of 

 older type. No recently developed group could have acquired such a 

 wide distribution of its simpler forms with so little modification. 



Calypogeia trichomanis and its Allied Forms.* — C. Meylan pub- 

 lishes some researches upon Galypogeia trichomanis Corda. This old 

 species has in recent years been divided into six species : C. trichomanis, 

 G. suecica, G. sphagnicola, G. submersa, G.fissa, C. Mulleriana. Meylan 

 has studied each of these species or subspecies carefully in the field and 

 under the Microscope. He divides his subject into two parts, treating 

 first of the forms which avoid growing in marshes, and secondly of the 

 marsh forms. Having to deal with plants mostly sterile, he employs 

 vegetative characters ; and, stating that the shape of the upper part of 

 leaf is of very little value owing to its variability on the same plant, he 

 prefers to employ as characters the shape of the amphigastria and the 

 areolation of the leaves. Having discussed the various forms, he con- 

 cludes that there are two types or well defined species : — C. trichomanis 

 and C. suecica, the first growing always on humus and bogs, the second 

 always on rotting wood ; that the former has the varieties Neesiana,fissa, 

 Sprengelii (with a form submersa) ; that the latter has a variety or 

 form erecta. He adds that there remains a group of forms which grow 

 associated with species of Sphagnum, namely G. sphagnicola ; but he 

 prefers to regard it, not so much a species, as a variety of the same value 

 as Sprengelii. In fine, G. trichomanis (exclusive of G. suecica) varies 

 enormously according to environment, producing a multitude of forms 

 useless to classify, as they grade into one another. 



Monograph of Philonotis.f — Gr. Dismier publishes a monograph of 

 the French species of Philonotis, and indeed of all the European species, 

 for he treats of all the other European forms of this difficult genus 

 which have been described as species. He bases the delimitations of the 

 species upon the form and direction of the cauline leaves, their areola- 

 tion, denticulation, flat or revolute margins, and the position of the 

 papillae on the cells. The species recognised by him are eight : — 

 P. rigida, P. marchica, P. capillaris, P. ccespitosa, P. fontanel, P. tomen- 

 tella, P. seriata, P. calcarea. The result is that the numerous puzzling 

 forms are gathered into clearly defined groups. 



* Rev. Bryolog., xxxv. (1908) pp. 67-74. 



t M6m. Soc. Sci. Nat. Math. Cherbourg, xxxvi. (1908) pp. 367-428. See also 

 Rev. Bryolog., xxxv. (1908) p. 83. 



