324 SUMMAEY OF CUKRENT RESEARCHES RELATING TO 



their natural conditions, yet this objection is of the less importance, 

 inasmuch as the aim of the investigator is to discover the influence of 

 external factors upon their form and growth. The author experimented 

 on a bilateral moss (Fissidens) and on an orthotropous dorsiventral 

 form {Dicranum). Fissidens is dorsiventral both morphologically and 

 physiologically, but may become bilateral on the clinostat. The various 

 heliotropic effects obtained by growth in the dark and also in a side 

 light are described. The geotropic propensities of the plant under 

 certain conditions are set forth. Similar observations were made on 

 Eurhynchiam striatum. Dicranum scopariinn is orthotropically geotropic ; 

 the stem is anatomically radial, liut physiologically dorsiventral ; in the 

 dark it, like F/ssideiis, puts out negatively geotropic rhizoids. Experi- 

 ments with side-light and witli the clinostat are described. The text is 

 illustrated with ;-i3 figures, and minute details are given of 42 experi- 

 ments. 



G-emmse-formation in Mosses. * — ^Y. J. Jongmans publishes his 

 observations on the following gemmiparous mosses — CEdipodium. Griffith- 

 ianum, Geoniia peJIuckla, and Aulacominum. He adds further details 

 of the life-history of (Edipodiinn Griffithianum, as compared with 

 other Splachuaceae, in which group it takes a rather independent 

 position. He describes the germination of the spore of (Edipodium, 

 which fonus first a filamentous and then a thalloid protonema, provided 

 at first with a two-sided apical cell. The origin and development is as 

 in Sphagnum, and not as in Georgia, Tetradontium , and Diphgscium. 

 Subsequently apical growth is replaced by marginal growth. The 

 gemmte are borne in the axils of the leaves of the mature plant, and 

 sometimes on the base of the leaf. They have two (rarely three) apical 

 cells, which grow out into flat thalli bearing secondary lobes, simple or 

 branched, like those of the spore-protonema. Between the gemmge and 

 the young leaves arise mucilage-hairs, which are homologous with 

 paraphyses, and, in the author's opinion, with the gemmae. In Georgia 

 peJlw'ida the gemmte arise directly from the two-sided apical cell, being 

 interspersed in the apictd cup of the stem with mucilaginous hairs of 

 equal origin. The secondary lobes of the protonema arise laterally, as a 

 rule ; they may be branched and show great power of regeneration. In 

 Aulacomniwn palustre the author found nothing at variance with the 

 observations of previous authors. The gemmse are metamorphosed 

 leaves, each gemma corresponding with an entire leaf-rudiment. In 

 A. androgynum four gemmfe are found on the rudiment of the leaf, and 

 arise from the leaf -portion of the segment ; the subsequently-produced 

 gemmae push up between them, but arise from the stem-portion of the 

 segment. In all the above species, except A. palustre, the origin of the 

 gemmffi can be traced back to protonema-formation, and the same can 

 be said of Tayhria Moritzii and some species of Splaclinohryum. 



New Splachnobryum and its peculiar Peristome.t — H. N. Dixon 

 describes Splachnobryum deliratulum, a new species of moss found by 

 G. Webster on brickwork in hot-houses at Baldersby and Harrogate. 



* Ueber Brutkorper bildende Laubmoose. Inaug. Dissertation Univ. Miinchen. 

 Nijmegen : Macdonald, 1907, 96 pp. (figs.). 



t Journ. of Bot., xlv. (1907) pp. 81-85 (1 pL). 



