50 J. H. ASHWORTH, B.SC. 



reserve food materials, of a downward-growing apex, on entering the 

 soil. In these tubers, Huge (loc. cit. p. 306) finds that the reserve 

 food materials contain considerable quantities of starch. 



Beyond these observations I have been unable to find any other 

 references to the tubers of Liverworts. 



The object of my investigation was to ascertain the structure and the 

 nature of the contents of the tubers of Anthoceros tuberosus. Unfor- 

 tunately, I have had at my disposal only dry herbarium material, but 

 I have been able to make out several new points of interest. 



Anthoceros tuberosus. The tubers occur on the ventral surface of the 

 thalloid expanse, and they lie embedded in the soil beneath the thallus. 

 They are spherical or pear-shaped, their diameter being "15 — -35 mm., 

 and the length of the stalk attaching them to the ventral surface 

 of the thallus -2 — -35 mm. (PI. III., Fig. 1). The wall of each tuber 

 is formed of three or fuur layers of more or less rectangular 

 cells, which are almost devoid of contents, there being only very 

 small remnants of protoplasm found in some of the cells 

 (Fig. 1, C). The walls of these cells are corky in nature, as 

 they are coloured yellow by iodine, and are not swollen or turned 

 blue by a subsequent treatment with strong sulphuric acid. Many of 

 the cells of the outermost layer, and some of the cells of the stalk, are 

 produced into hair-like processes, attaining a length of *25 mm. (Fig. 

 1, H.). These do not appear to be cut off by a cell wall from the cells 

 from which they arise. The walls of these hairs, and also of the cells 

 of the basal part of the stalk, differ slightly in composition from the 

 corky cell walls, as on treating with iodine and sulphuric acid they 

 stain slightly bluish-green, but do not swell appreciably. These cell 

 walls appear to be cellulose which has become almost transformed to 

 cork. The hairs are probably the remains of absorbing organs (the 

 rootlets mentioned in the Synopsis) which performed some function 

 during the formation of the tuber. 



Within the protective cells, lie closely-packed cells, all of which con- 

 tain food materials. The cell w r alls of this portion of the tuber are thin, 

 and of unchanged cellulose (PI. 2, Fig. 2). Each cell contains a large, 

 central, usually elongated nucleus (N), a large number of colourless 

 or slightly yellow round or oval granules (G), imbedded in the remains 

 of the protoplasm (P), and numerous small oil drops (0), or one large 

 one due to the coalescence of the smaller drops. 



