ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 197 



xylem cells mostly disappear with age. Sclerencliymatous elements 

 seldom occur in tlie stele. Rhizome and root were not examined in 

 anatomical detail. Angiopteria evecta is remarkable for its polyarch 

 bundle. According to the development of the frond, ferns fall into 

 three groups : — 1. The epidermis and mesophyll are almost similarly 

 developed. 2. The mesophyll is a typical spongy- and palisade- 

 parenchyma, quite different from the epidermis. 3. The mesophyll is 

 very thin-walled and large-celled, and quite different from the ejoidermis. 

 In some ferns there is a hypodermis in the frond. Only those forms 

 of frond that are more than eight layers thick are mechanically stiffened 

 along the margin. 



As regards cell-contents, chlorophyll rarely occurs in the epidermis of 

 the leaf-stdk, not as a rule in the sclerenchymatous ring, never in the 

 endodermis, but it does occur in the stele, and still more in the main 

 parenchyma. The amount of chlorophyll increases from the base 

 upwards. Tannin occurs everywhere, and mostly dift'used : in the 

 " stiitzscheide " it is more abundant than in the main parenchyma ; it 

 is nearly always present in the stele, but in the endodermis it is as 

 often absent as present. Tannin is never found in the sieve-tubes, 

 and the tannin-ideoblasts are not very frequent in the outer layers, nor 

 in the stele. Tannin, like chlorophyll, increases from below upwards. 

 Accumulations of tannin occur in certain parts of undeveloped or 

 dying leaf-stalks. Starch is rare in the epidermis and in the scleren- 

 chyma-ring ; is always present in the main parenchyma, sometimes in 

 great quantity ; but never occurs in the endodermis and protophloem. 

 The amount of starch either diminishes or increases from the base up- 

 wards. Oialate has been found in four cases only. In the /ronrfthe 

 distribution and occurrence of chlorophyll, tannin, starch, and oxalate 

 is similar to that in the leaf-stalk, and the same applies to the rhizome 

 and root. A. G. 



Further Note on the Ecology of Phyllitis hybrida. — V. Vouk 

 {Oesterr. Bot. Zeitschr., 1916, 66, 3!)7-99 ; see also Bot. CentraVbl., 

 1918, 138, 138). This species is regarded by the author as a meso- 

 phyte with well-developed xerophytic adaptability ; in • contrast to 

 Morton, who regards it as a typical hygrophyte with great capability of 

 adaptation. Phyllitis hybrida and Ceterach are considered euryphotic 

 plants, while P. hemionitis is stenophotic. P. hybrida and Ceterach 

 could also be called euryxerophil, and P. hemionitis stenohygrophil. 



E. S. Gepp. 



Bryophyta. 



Critical Revision of Carl Muller's Moss Genera. II. — Max 

 Fleischee {Heclwigia, 1917, 59, 212-19 ; see also Bot. Centralhl., 1918, 

 138, 153). A continuation of the critical examination of C. Miiller's 

 herbarium. A new genus, Pterogoniadelphus, is founded, between 

 Forstroemia and Pterogoniiim, with the species P. montevidensis 

 (= Cladomniimi montevidense C.M.). Leucodon levifoUus Broth, ined. 

 is placed in Hypnum sect. Pterogoniojjhyllum Flsch. (a new section). A 



