476 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Nature of Algal or Boghead Coal.* — E. C. Jeffrey discusses the 

 nature of so-called algal or boghead coals, which have been described as 

 consisting of the remains of oil-containing groups of gelatinous green 

 alga3. The opacity and brittleness of material make the preparation of 

 slides sufficiently thin for satisfactory examination almost impossible. 

 Chemical treatment of the coal was without result until the following 

 method was devised :— exposure to nitro-hydrofluoric acid for a time ; 

 careful washing ; soaking in hot alcohol containing from 3 to 5 p.c. of 

 fixed alkali. The coal swells and softens without cracking, and after 

 infiltration with nitro-cellulose, can be cut with the razor into very thin 

 sections, which can be bleached with nitric acid and strong chlorine 

 water. It is then found that these coals consist not of alga;, but of 

 macrospores of vascular Cryptogams. The " algaB " are, in fact, only 

 the pores in the strongly sculptured coats of these macrospores. The 

 typical tri-radiate ridge is present. The " alga3 " have been named 

 Thylax, Pila, and Reinschia. 



Adaptation of Ferns to Light. f — L. Lammermayr publishes a 

 further contribution on the adaptation of ferns to different strengths of 

 light. His investigations were made upon species of the Mediterranean 

 and Alpine regions Ceterach ojftcinarum, Gheilanthes fragrans, Adiantum 

 Gapillus- Veneris, Asplenium Adiantum-nigrum, A. serpentini, Aspidium 

 rigidum, Scolopendrium vulgare. Among his general conclusions he 

 says that the only native fern which enjoys the fullest exposure to 

 bright light is Pteridkmi aqidlinum. In the second line come 

 Ceterach, Gheilanthes, Asplenium, xerophilous species of walls and rocks. 



Urostachys, a subgenus of Lycopodium.J — W. Herter publishes a 

 contribution to a knowledge of Lycopodium, especially the subgenus 

 Urostachys. He has studied the collections of eighteen herbaria. After 

 giving a resume of previous works treating of the subject, he devotes a 

 chapter to the consideration of the characters which are available for 

 the systematic classification of the species. The mode of ramification is 

 of the greatest value in Urostachys, being a regularly repeated dichotomy. 

 Next, the leaves are of great importance, according to their close or 

 scattered disposition on the stem, their erect or spreading position, their 

 texture, size and form ; also the colour of the axis and leaves. The 

 members of Urostachys are all mesophytes and grow on humus. 

 Reproduction takes place by means of spores and much more by bud- 

 production. Urostachys flourishes mainly in the tropics, especially in 

 tropical America and in the East Indies. The author provides a key to 

 the subgenera and sections, and arranges the 140 species in systematic 

 order, giving descriptions of 48 that are new to science. 



North American Ferns. — J. H. Ferriss§ gives an account of the 

 ferns of Cochise county in the south-east corner of Arizona. Some 

 sixty species of ferns and fern-allies have now been reported for the 



* Rbodora, xi. (1909) pp. 61-3. 



t X. Jahresber. k.k. Staatsgymn. Leoben, 1898, pp. 3-14 (pi.). See also Hedwigia, 

 xlviii. (1908) Beibl., p. 116. 



J Engler's Bot. Jahrb., xliii. Beibl. No. 98 (1909) 56 pp. (4 pis. and figs.). 

 § Fern Bulletin, xvii. (1909) pp. 1-7. 



