1913-14.] BOTANICAL SOCIETY OF EDINBURGH 245 



There are also differences of structure in both nerve and 

 pagina. etc. 



npylopus citrescens, n. sp. In lax tufts of a pale 

 green colour above, which changes in the herbarium to a 

 lemon-yellow, stems short, about half an inch long, almost 

 always simple, leaves nearly upright and straight whether 

 wet or dry. lengthening somewhat in an upward direction. 

 from a slightly ovate base, concave above, having as a rule 

 a few rather strong red radicles at base of leaf as well as 

 very tine red or rather purple tomentum which shows more 

 or less throughout the lower part of the tuft : nerve red 

 at base, including corresponding part of pagina. yellow 

 thereafter, three-fourths breadth of base, tapering and longly 

 excurrent : no auricles at basal margin and leaf narrows 

 there : central basal cells, in two or three perpendicular rows, 

 large, oblong, attached with thick transverse opaque walls. 

 the lateral walls thin. 'Ooo-'OT by 'OIS-OIT mm., becoming 

 narrower outwards to margin and hyaline, the latter pro- 

 ceeding farther up the leaf than the others, becoming 

 shorter and showing many bright points but no chlorophyll, 

 such soon cease in single file on the nerve, upwards the nerve 

 is predominant. Plockton. Sept. 1913. 



This moss is peculiar in several respects, inasmuch as the 

 nerve is non-cellular in its posterior half and no upper cells 

 are perceptible, in the citrine colour, and in the presence of 

 both kinds of fibrillae. 



As regards this moss. I think it right to make known 

 certain phenomena observed in connection with the large 

 red radicles attached not to the nerve, as is almost invari- 

 ably alleged, but to one of the large cells already alluded to 

 and situated close to the nerve. It was noticed that these 

 radicles had their origin from a large, irregularly oblong, 

 opaque body situated between the double walls of such 

 cells now turned red and thickened. A gentle pressure on 

 this body by means of the glass cover caused it to expand 

 a little. Leaving the whole for two hours, but renewing the 

 moisture three or four times during the interval, I became 

 aware of the darkening of the end opposite to that of the 

 point of attachment of the radicle and of the appearance 

 of a slight notch at its summit, while slender threads were 

 visible here and there over its general surface. Unfortu- 



