440 SUMMARY OF CTTRRENT RESEARCHES RELATING TO 



is ordinarily called the protonema ; (2) the bryophy tic phase, the equivalent 

 of which is jieculiar to this group ; (3) the phanerogamic phase, commonly 

 called the asexual generation. The fertilized oosphere of mosses, like that 

 of Phanerogams, gives birth directly to an embryo destined to produce 

 definite organs. This is not the case with Vascular Cryptogams, and the 

 Muscinefe are hence less differentiated from Phanerogams than are Vascular 

 Cryptogams, in which the stem, root, and leaf are developed directly at 

 the expense of the oosphere. The sporogonium of mosses is a derivative of 

 the tigellum, in the same sense as the stem of higher plants ; in the foot 

 and the sporogonium are found all the anatomical regions of the stem, 

 cortex, epidermis, endoderm, pericycle, and medulla. The spores originate 

 from the pericycle. 



HeterosporoTis Muscineae.* — In addition to the examples already given, 

 Herr C. Warnstoff records the occurrence of microspores in Sphagnum 

 cuspidatum and cymhi folium. He believes them to be not accidental struc- 

 tures, but to be homologous to tlie microspores of the heterosporous 

 vascular cryj^togams, probably producing on germination a male pro- 

 thalliiim. 



Herr Warnstoff has also detected two kinds of sjiore in some Hepaticfe, 

 especially in Blyttia LijeUii. The long cylindrical capsules, which split 

 into four lobes, contain both large roundish-tetrahedral and small spherical 

 spores, the former having a diameter of from ' 021 to ■ 025 /x, the latter from 

 0' 012 to 0* 016 /x. Though the germination of the spores has here also not 

 been actually observed, he believes that the macrospores produce female, 

 the microspores male individuals. 



Distribution of Mosses, j — M. E. Hult describes in detail the moss-flora 

 of Finnish Lapland, amounting to 285 species, including 51 Hepaticfe and 

 15 SphagnaceaB. He discusses the causes which are most efficacious in 

 promoting the distribution of mosses, and gives reasons for doubting the 

 prevalent theory that it is mainly due to the spores being carried great 

 distances by the wind. 



Algae. 



Gelatinous Sheath of Algae. :J: — Herr G. Klebs has examined critically 

 the structure and origin of the gelatinous sheath which invests the filaments 

 of many algfc, and also some Fhigellata. 



In the Zygnemacefe this sheath is composed of a substance entirely 

 independent of the cell-walls. It consists of two portions : — a homogeneous 

 substance which is but slightly refringcnt, and which is indifferent to the 

 action of staining reagents, and a portion which absorbs pigments (methyl- 

 blue, methyl-green, vesuvin, &c.) with avidity, and which is composed of 

 minute rods at right angles to the cell-wall. Under the action of Prussian 

 blue it swells, becomes irregular, and finally disorganized. These reactions 

 are exhibited only by the sheath of the living plant. Its substance does 

 not comport in its reactions with the ordinary mucilage of vegetable cells ; 

 it is not dissolved by alkalies ; treated with hot water or with chloriodide 

 of zinc it loses its power of absorbing pigments. The author maintains 

 that the substance of the sheath is derived directly from the cytojilasra of 

 the cells through the cell-wall. It is always quite distinct from the cell- 



* Verliandl. Bot. Ver. Prov. Brandenburg, 1886, pp. 181-2. See Bot. Centralbl., 

 xxix. (1887) p. 198. Cf. this Journal. 1886, p. 830. 



t Acta Soc. pro Faun.i et Flora Fennica, iii. (ISSG). See Bull. Soc. Bot. France, 

 viii. (18SG) Eev. Bibl., p. 193. 



X Unters. Bot. Inst. Tubingen, ii. (1886) pp. 3.33-418 (2 pis.). 



