336 SUMMARY OF CURRENT RESEARCHES RELATING TO 



unisexual or whether they bear male and female inflorescences. The 

 authors answer these questions after observing for some months pure 

 cultures of Barbula unguiculata, Bryum argenteum, and Ceratodon pur- 

 pureus. Detailed descriptions are given of the precautions taken for 

 obtaining pure cultures, the composition of the nutritive solution 

 employed, sterilising methods, etc. The authors find that the spores of 

 one and the same capsule give rise to protonemas of different sexes. 

 The fructifications of a second year's stem are always of the same gender 

 as those of the preceding year. Protonemas are either male or female, 

 and they never produce organs of both sexes. Secondary protonemas, 

 i.e., those arising from adult stems under certain conditions, retain the 

 sex of the stem from which they arise. Physical external influences, 

 such as modifications of nutritive media, etc., do not affect the sexuality 

 of the protonema. 



Key to British Hepatics.* — S. M. Macvicar publishes a revised 

 key to the British Hepatics. For the benefit of beginners it is planned 

 largely on superficial characters. Advice is given in the preface as to 

 how specimens ought to be examined, and as to the importance of deter- 

 mining the position and character of the perianth, and the nature of the 

 inflorescence. A fundamental factor in the grouping of the genera is 

 found in the underleaves — their absence or their relative size when 

 present. Keys to the species are added under the genera. 



New British Hepatic, f — W. H. Pearson describes and figures 

 Porella laevigata var. kiUarniensis, a new variety found by him at 

 Killarney in 1905. He has re-examined this variable species, and 

 arranged the numerous specimens which he has studied into four groups. 

 The typical form has the antical leaf -lobes acute, with two or three teeth 

 near apex. Var. acuta Pears., is much commoner, and has the antical 

 lobes acute, often apiculate, uncinate, margin entire. Var. subintegra 

 Kaal., has margin entire, apex rarely acute. The new var. kiUarniensis 

 is an extreme development of the typical form, usually larger, lighter in 

 colour, pale green above, ochraceous below ; it grows in loose graceful 

 tufts, and has the antical leaf -lobes spinulose-dentate above the middle. 

 The polished cuticle and acrid taste refer this variety to P. laevigata. 



British Hepatics. — TV. Ingham % records an important variety of 

 Kantia trichomanis, which he describes under the name of var. aquatica. 

 Hitherto it has been found in only two localities, Buckden Pike and 

 Deepdale, both in Upper Wharf edale. Its main characteristic lies in 

 the very decurrent leaves, which give the stem a winged appearance, 

 and in the ovate and deeply-divided stipules. The author records also 

 32 hepatics and 42 mosses as rarities in Yorkshire and Durham, and 

 adds a note on teratology in mosses. C. E. Larter § gives a list of 19 

 hepatics, apparently not previously recorded for North Devon, and a 

 similar list of 12 for South Devon. J. A. TVheldon|| confirms his pre- 

 vious record of Marchantia polymorpha var. aquatica as occurring at 



* Eastbourne : Sumfield (1906) 19 pp. 



+ Journ.of Bot., xliv. (1906) pp. 81-3 (1 pi.). 



t Rev. Bryolog. xxxiii. (1906) pp. 6-13 (figs, in text). 



§ Journ. of Bot., xliv. (1906) p. 105. || Tom. cit., pp. 105-6. 



