998 "* SDMMABY OF CURRENT RESEARCHES RELATING TO 



functional cell are filled by delicate strands of protoplasm ; these establish 

 a direst continuity between the protoplasmic contents of the various cells of 

 the hair. The authors believe that, in their main features, the phenomena 

 attending the formation of the secretion are very widespread, and limited 

 neither to ferns nor to the particular case of secretion of mucilage. 



Leaves of Ferns.* — Herr A. Vinge notices some peculiarities in the 

 structure of the leaves of ferns, corresponding to the needs of the species 

 as regards transpiration. In many thin-leaved ferns the mesophyll is 

 almost entirely undifferentiated. Not unfrequently we find intercellular 

 prolongations from the walls of the mesophyll-cells, especially in the 

 neighbourhood of the stomata. The thick leaves of Adianium macrophyllum 

 have a very loose tissue ; while, on the other hand, the mesophyll of 

 Polypodium ireoides is very dense. The greatest differentiation of tissue 

 was found in Niphobolus Lingua. Beneath the upper epidermis, a hypoderm 

 consisting of two layers, then a palisade-parenchyma of from one to three 

 layers with the ordinary isodiametrical layers within, the whole structure 

 closely resembling that of a dicotyledonous leaf. 



Muscineee. 



Fructification of Grimmia Hartmannj.t — M. Philibert describes this 

 moss as resembling in the sterile state Bkacomitrium sudeticum, from which, 

 however, it is distinguished by the tissue of the leaves. The perichsetial 

 leaves are of the same shape as the caulino leaves, only their base is rather 

 more sheathed, and the tissue in the lower part is composed of rectangular 

 cells, which are looser and more transparent. Earely two fruits come 

 from the same perichsetium. The pedicel is three or four millimetres in 

 length and twisted into a spiral ; when moist, it is bent in an arc, so that 

 the capsule is at an angle of about 45° with the vertical. The capsule is 

 oval-oblong, very smooth, and is pale in colour with a reddish margin. 

 Its length without the operculum from 1*5 to 1"7 mm., the diameter 

 from 0"75 mm. The operculum is conical, subulate, and slightly oblique. 

 The teeth of the j)eristome are linear-lanceolate, obtuse, entire, and of an 

 orange-red colour ; the two lower rows are very smooth. In conclusion, 

 the author states that Grimmia Hartmanni ought to be placed among the 

 true Grimmise near to G. contorta Wahl. 



Sphagnacese of North America.^ — In a revision of the Sphagnaceae of 

 North America, M. J. Cardot states that that continent possesses several 

 subtropical types not found in Europe, while only one European form 

 (^S. Angstroemii) is at present absent from it. 



Algae. 



Siplione8e.§ — The most recently published part of Prof. J. G. Agardh's 

 Classification of Algae refers to this group, in which he includes Dasycla- 

 dacese and Valoniace^. The whole group is divided by him into six families 

 as follows : — I. Bryopside^ {Bryopsis, Derhesia f). II. SpoNGODiEa; 

 {Codiumi, Cladothele). III. Udotbaobze (Ghlorodesmis, Avrainvillea ?, 

 Espera, Penicillus, BJiipocepTialus, Callipsygma n. gen., Udotea, Hhipido- 

 siphon f, Halimeda). IV. Valoniace^ ( Valonia, Siphonocladus, Ascothamnion ?, 



* Bot. Centralbl., xxxi. (1887) pp. 290-3. f Kev. Bryol., xiv. (1887) pp. 49-52. 



X Bull. Soc. Bot. Belg., xxvi. (1887) pp. 44-61. 



§ Agardli, J. G., ' Till Alpernes Systematik,' in Lunds Univs. Arsskr., xxiii. (1887) 

 180 pp. and 5 pis. See Mrs. Merrifield, in Nature, xxxvi. (1887) p. 313. 



