08 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Notes on Hippochsete." — 0. A. Farwell, who prefers the name 

 Hippoclmte for the scouring-rush section of Eqimetum, publishes notes 

 on Hippochaete laevigata and H. prealta. The type of the former is 

 Eqimetum Jsevigatum A. Br., which has been misunderstood through 

 Braun's error in regarding it as a perennial stemmed species. But a 

 careful analysis of the original description identifies the plant with the 

 smooth annual stemmed species, E. kansanum Schaffner. In clearing 

 away some errors with reference to H. prealta (Raf.) he finds a variety 

 without a valid name, and proposes for it the varietal name pseudo- 

 hyemalis. 



Pellsea in North America.f— F. K. Butters publishes some notes 

 on Pellsea atropurpurea (L.) Link and P. glabella Mett. ex Kuhn. From 

 a careful study of herbarium specimens and living material he is able to 

 show that the ranges of these two species barely overlap, P. glabella 

 having a northern, and P. atropurpurea a southern range in North 

 America. They are perfectly distinct species, as F. L. Pickett % has 

 indicated. To the specific differences brought out by Pickett sofiie 

 further points are added by Butters in respect of the structure of the 

 scales and the spores. There are two western varieties of P. glabella— 

 one, var. simplex, a novelty which the author describes ; and the other, 

 var. occidentalis (E. Nelson), which has been confused with P. Breiceri 

 and P. atropurpurea. Finally, the author gives the distinctive characters 

 and the range of P. Breweri Eaton. 



'a^ 



American Fern Notes. §—0. A. Farwell, in publishing a series of 

 notes on ferns, calls attention to Sir John Hill's " Family Herbal " 

 (1755) and to his use of Fdix (p. 171) in a generic sense, and gives a 

 list of new combinations of North American species transferred from 

 Dryopteris to Filix. The notes on Ophioglossacese include a number of 

 new varietal combinations, and a new variety Botrychium multifidum, 

 var. dichotomum, which is described and figured. Lgcopodium obscurum 

 L. is discussed, and a new variety {hybridum) is constituted, which repre- 

 sents L. dendroideum Willd. (non Michaux). L. complanatum and its 

 varieties are discussed, and a key to the latter is provided. 



Pern Prothallia.|l— G. Klebs has made a study of the physiology of 

 the developing fern prothallia. The first part deals with the influence 

 of light and temperature upon development. Experiments were made 

 principally with the spores* of Pteris longifolia, and the results were as 

 follows : 1. Light is, with few exceptions, necessary for the germination 

 of the spores, and the resulting organism develops differently according 

 to the intensity of the light. These are described in detail, with the 

 corresponding degree of candle-power. 2. The primary rhizoid arises 



* Amer. Fern Journ., vii. (1917) pp. 73-6. 

 t Amer. Fern Journ., vii. (1917) pp. 77-87. 

 X Amer. Fern Journ., iv. (1914) p. 97. 



§ Eighteenth Annual Report, Michigan Acad. Sci., 1916, pp. 78-94. 

 II Sitzungsber. Heidelberg Akad. Wiss. Math.-Naturw. KI. B., 4 Abhandl. 

 (1916) pp. 3- 82 (figs.). See also Bot. Centralbl., cxxxiv. {1211) pp. 220-2. 



