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published descriptions. It is unfortunate that well-developed bracts of B. 

 denudata are still unknown. 



The perianth of B. ambigua is narrowly ovoid, measuring about 3 mm. in 

 length and 1 mm. in diameter. Three rounded keels are present and these are 

 separated above the middle by grooves. The contracted mouth is minutely 

 and irregularly spinulose-denticulate. 



The valves of the brown capsule measure about 1 X 0.5 mm. The cells 

 of the outermost layer are in more or less distinct longitudinal rows and average 

 about 28 ix in length by 14 ju in width. The thickenings, usually one to three in 

 each cell, tend to be restricted to alternate longitudinal walls, the intervening 

 longitudinal walls and the transverse walls being free from thickenings or nearly 

 so. The cells of the innermost layer are somewhat longer but scarcely narrower 

 than those of the outermost layer. On the inner tangential walls distinct or 

 poorly developed thickenings in the form of half-rings can be distinguished. The 

 minutely punctulate, brownish green spores are 12-14 M m diameter, and the 

 elaters, each with two brown bands of thickening, are rounded at the ends and 

 measure 200-250 n in length by 8-10 n in diameter. 



Vegetative reproduction in B. ambigua, by means of caducous leaves, is a 

 very striking phenomenon, and many tufts show numerous examples of long 

 slender branches with neither leaves nor underleaves except at the apex. The 

 process is essentially the same as in B. denudata, where it has already been 

 described, 1 so that it will be unnecessary to enter again into the details. 



Some of the specimens collected by Macoun on "rocks near the sea," at 

 Ucluelet, British Columbia, are decidedly aberrant, owing probably to their 

 exposed habitat. They are deep brown in color, they exhibit the caducous 

 habit to some extent, and their leaves are narrow. They show in consequence 

 a strong superficial resemblance to European specimens that have been referred 

 to " B. triangularis Pears." or. perhaps better, to " Pleuroschisma tricrenatum 

 var. implexum K. Mull. " In certain cases, however, branches with narrow leaves 

 are found on plants which bear also branches with the broader bidentate leaves 

 characteristic of B. ambigua, so that the determination of Macoun 's more 

 doubtful specimens as B. ambigua seems allowable. 



8. Bazzania nudicaulis sp. nov. 



Collected May 28, 1892, on rocks, summit of White Top Mountain, Virginia 

 (5675 ft. alt.), by J. K. Small (No. 54, in part); also August 3, 1919, on rocks, 

 High Bluff of Roan Mountain, North Carolina (over 6000 ft. alt.), by A. L. 

 Andrews (No. 65); also June 16, 1923, on rocks (and tree-roots), Grandfather 

 Mountain, North Carolina (5964 ft. alt.), by P. O. Schallert (No. 19, in part). 

 No. 65 from Roan Mountain may be considered the type. 



Scattered or growing in depressed mats, often in admixture with other 

 bryophytes, varying in color from pale yellowish brown to dark brown or almost 

 black: stems mostly 1-2.5 cm - long and (with the leaves) 0.7-1.5 mm. wide; 

 lateral branches infrequent, diverging at a rather wide angle; \entral branches 



1 Rhodora 25! 93. 1923, 



