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tics, usually species of Lejeunea (in its broad sense), Frullania and Plagiochilla. In 

 the North Carolina material Frullania Asagrayana Mont, and a small sterile 

 Plagiochila with caducous leaves are present in some abundance. On account of 

 its minute size the Mylia is often difficult to detect in these admixtures, an in- 

 dividual stem being almost invisible to the naked eye. Full and accurate descrip- 

 tions of the species are given in recent European manuals, 1 and the following 

 account is largely a compilation. The European material studied by the writer 

 was collected by Macvicar at Moidart, some of it having been distributed in 

 Schiffner's Hepaticae Europaeae Exsiccatae, No. 250, as Leptoscyphus cuneifolius . 



A more or less distinct brown pigmentation is usually present in both leaves 

 and stems. The latter are mostly simple but occasionally give off one or more 

 ventral intercalary branches from the axils of the underleaves. According to 

 Kaalaas, who gave an unusually full description of the species in citing it as a 

 Norwegian plant, the stems may attain a length of 1 cm. as a maximum, but a 

 length of only 3-5 mm. is much more usual. The diameter averages about 0.05 

 mm. Rhizoids are very scantily produced and seem to be restricted to the bases 

 of the underleaves. 



The slightly concave leaves, which spread somewhat from the stem, are 

 usually far apart and show an almost transverse insertion. When well developed 

 they measure 0.15-0.2 mm. in length, but considerably smaller leaves are not 

 infrequent. Although the shape is variable, a tendency to broaden out from a 

 narrow base is usually apparent, giving in most cases obovate or obcuneate out- 

 lines, with a rounded, truncate or slightly emarginate apex. The leaf-cells average 

 about 18 n in diameter and vary but little in size in the different parts of a leaf. 

 They are distinguished by their smooth cuticle, pigmented walls and well-defined 

 trigones, often with convex sides. 



According to the older descriptions the underleaves of M. cuneifolia are 

 acutely bifid. This condition, however, as the later descriptions testify, is very 

 rarely attained. Most of the underleaves are narrowly to broadly lanceolate, 

 with an acute or acuminate apex and perfectly entire sides. Occasionally a 

 blunt tooth is present on one side or even on both. The underleaves spread more 

 or less widely from the stem and average about 0.1 mm. in length and 0.05 mm. 

 in width. As Kaalaas states each underleaf adjoins a lateral leaf on one side of 

 the stem but is distant from the lateral leaf on the other side. He adds that there 

 may be actual coalescence between the underleaf and the lateral leaf, but the 

 writer has been unable to confirm this statement. 



In the absence of sexual organs the species reproduces itself vegetatively 

 by means of caducous leaves, which are sometimes thrown off so copiously that 

 the stems appear almost leafless, except for the persistent underleaves. Schiffner 

 has described the process very clearly. 2 He interprets the caducous leaves as 

 "Bruchblatter," rather than "Brutblatter, " in the terminology of Correns, 

 because there is no predetermined zone of separation, the leaves breaking off in 



•See especially Macvicar, Student's Handb. British Hepatics 231 (with figures). 1913. 

 2 Oesterr. Bot. Zeitschr. 57: 457. 1907. 



