72 HEVUE BRYOLOGIQUE 



E — Part of a vertical section of the Ihallus, shoAving three of the wide thin- 



x\'aUed rhizoids ; on the left the branched free end of a rhizoid is 

 shown. X 120. 



F. — Part of a section showing one of the narrow thick-walled rhizoids in 



longitudinal section, and three others in cross-section X ''^O. 



This envelope is finely granular and gives the reactions of proto- 

 plasm. 



Many of the internal cells of^llie thallus contain starch-grains, 



and the walls are frequently marked by slit-like pits. Ruge* 



found crystals of calcium oxalate in the internal cells of a South 



American Monoclca {M. Gollschei?)^ and Stephanij- states that 



crystals occur in the superficial cells of the Ihallus in both species 



of lliis genus. The writer has never observed any crystals in 



fresh material, but in plants that had been kept in alcohol, even 



for a. few days, nearly every cell of the thallus showed, in sections, 



a single small spherical cluster of radiating needle-like crystals. 



Without being able to stale dotlnitely the nature of these crystals, 



the writer is inclined to think that they do not consist of calcium 



oxalate. They are rapidly dissolved in hot water, slowly in 



cold, and probably consist of inulin. The occurrence of these 



crystals is of interest, as bodies of this kind arc rarely 



found in the tissues of the Ilepatica^. Masses of calcium 



carbonate occur in the thallus of /Jlaskt and the closely allied 



Caviciilaria, and Kusterf has described Ihe occurrence in 



Ccphalozia bicmpldala of tabular crystals, probaldy calcium 



oxalate. 



The growing-point of the thallus lies in a deep notch^ and 

 consists of a small group of wedge-shaped initial-cells; in most 

 cases, at any rate, it is hardly possible to distinguish a single 

 initial, and a horizontal section (Fig. 2, C.) through the growing- 

 point presents the same appearance as in the case of the Mar- 

 chantiaca?. From the superficial cells immediately below the 

 growing-point tijere grow out some very large club-shaped 

 mucilage-hairs, each consisting of a single cell. These large cells 

 (Fig. 2, B.) have thin \vaHs and highly mucilaginous snp, the 

 protoplasm lacing reduced to a thin layer lining the cell-wall. 

 Tliey soon become withered and disorganised, so that Ihey can 



tr 



* Beitrage zur Kenntniss der Vegetationsorgane der Lebermoose. Flora, 

 1893, p. 10. ^ 



t Species Ilepaticarum. Vol. i. Anacrogytise (1900), p. 351. 



X Die Oelkorper der Leberurioose and ilir Verljaltnis zu den Elaioplasten. 

 Inaurj. Diss. Univ. Easel, lS9-i, p. 39. 



