-6 3 - 



sometimes sparingly produced and sometimes more abundant, usually flagelliform 

 but occasionally similar to the lateral branches; rhizoids absent altogether or 

 very sparingly produced, apparently restricted to the minute leaves of the 

 flagelliform branches: leaves distant, 0.5-0.65 mm. long and 0.3-0.45 mm. 

 wide when well developed but often considerably smaller, obliquely to widely 

 spreading, plane or somewhat convex, ovate to ovate-lanceolate, usually scarcely 

 rounded at the dorsal base but sometimes distinctly rounded or even subcordate, 

 both upper and lower margins somewhat arched, apex narrowed and very variable, 

 sometimes undivided and acutely or obtusely pointed, sometimes with two or 

 (rarely) three short and sharp or blunt teeth, separated by acute to rounded 

 sinuses; leaf-cells averaging about 25 X 20 n in the median portion and 16 m 

 in width along the margin, trigones of fair size but inconspicuous, with slightly 

 concave to straight sides, cuticle smooth throughout : underleaves distant, quad- 

 rate-orbicular, mostly 0.4-0.45 mm. long, exauriculate at the base, the sides 

 slightly bulging and the apex truncate, sometimes emarginate and sometimes 

 with three or four crenations: sexual branches not seen; vegetative reproduction 

 by means of caducous leaves and underleaves, usually abundantly produced. 



The throwing off of leaves and underleaves as "Bruchblatter," which is 

 so striking a phenomenon in B. ambigua and B. denudala, is even more pronounced 

 in B. nudicaulis. Many of the plants, in fact, are wholly leafless for long stretches 

 and present the appearance of fine wires, yellowish or brownish in color and more 

 or less interwoven. In some cases large and fairly well-developed leaves become 

 separated from the axis, but the caducous habit, as in B. denudala, is more uni- 

 formly associated with branches bearing smaller leaves. The majority of such 

 branches arise laterally and conform to the normal Frullania type, but it is not 

 unusual for a ventral branch to assume the caducous habit, instead of developing 

 as a flagelliform axis with minute and persistent leaves. No cases have yet been 

 observed, however, in which a ventral branch changed its character during the 

 course of its development. 



In spite of its somewhat more robust habit Bazzania nudicaulis bears a certain 

 superficial resemblance to Mylia cuneifolia. Both species are characterized by 

 distant leaves, well-developed underleaves and a more or less marked pigmenta- 

 tion, and both exhibit a vigorous vegetative reproduction by means of caducous 

 leaves or Bruchblatter. Here, however, the resemblance ends. The branches 

 in the Mylia seem to be always ventral, the leaves are almost transversely 

 inserted and tend to broaden out toward the apex, while the underleaves are 

 narrow and usually undivided and sharp-pointed. In the Bazzania, on the other 

 hand, lateral branches can always be demonstrated, the leaves are incubous and 

 narrow toward the apex, while the underleaves are broad and truncate. 



As Schiffner has pointed out the caducous leaves of Mylia cuneifolia give 

 rise to new plants by the regeneration (or germination) of marginal or basal cells. 

 In Bazzania nudicaulis and other species of Bazzania with caducous leaves the 

 regenerative process seems to be less restricted, a new plant often springing from 

 a cell in the interior of a leaf. Such a cell may even be situated in the apical 

 halt of a leaf, although a position nearer the base is more frequent. Regeneration 



