Notes. 
137 
what complex structure \ They are perhaps as much like Lepidocarpon as Mazo- 
carpon . 
I trust I have adduced sufficient evidence to show that there is no adequate 
ground for assuming the existence of a sporangiophoric Lepidophyte. On the other 
hand, most of the remarkable specimens now for the first time collected and figured 
by Bassler are welcomed as further examples of Sigillarian microsporophylls, of which 
we had hitherto only one incrustation record (Kidston, loc. cit., PI. II, 1, esp. d'). 
M. BENSON. 
Royal Holloway College, 
University of London. 
ON THE GEMMAE OF TORTULA MUTICA, LINDB. Among mosses, the 
production of gemmae is a comparatively rare phenomenon, as is seen from the fact 
that of the six hundred and twenty odd British species adopted by Braithwaite 1 only 
seventeen are known to reproduce themselves in this manner. 
In these seventeen species the form and origin of the gemmae are exceedingly 
Various. They may be red, club-shaped, septate processes which become detached 
from the margins of the leaf; or they may grow in clusters at the leaf-apex. More 
complicated gemmae are sometimes met with in the axils of the leaves, and these are 
often red and may develop directly into bulbils which become detached from the 
parent plant. In the most highly specialized plants the gemmae are borne within 
special cups of leaves, or on leafless pseudopodia. 
Braithwaite records that in one specimen of Tortula mutica which he had examined 
there were ‘ minute globular gonidia scattered over the surface of the leaf, not unlike 
those in Tortula papillosa \ 2 His record is extremely brief, and no figure is given. 
Recently, however, a specimen of Tortula uiutica from North Wales has been 
examined, and was observed to bear numerous gemmae. They were simple in form 
and were usually borne scattered over the surface of the leaf. Each consisted, as 
a rule, of two (Fig. 3) or four (Figs. 2 and 5) cells bounded by thick, reddish-brown cell- 
walls, and containing dense granular protoplasm and a number of large, circular or 
somewhat irregular, discoid chloroplasts. Occasionally larger gemmae were found 
(Fig. 4), and in these the disposition of the cells was more irregular than in the 
smaller gemmae. The gemmae were attached to the leaf of the mother-plant by 
means of a single colourless stalk-cell, which grew from the surface of one of the 
cells of the blade, as shown in Fig. 2. The chloroplasts in the gemmae were very 
much larger than those in the cells of the leaf-blade, while their colour was a deep 
bluish-green, far more intense than that observed in the leaf itself. 
Much more rarely, gemmae were found growing laterally on protonema-filaments 
whose walls had assumed a brown colour almost as dark as that of the cell-walls of 
the gemmae, and whose contents were destitute of chloroplasts. These gemmae 
were attached to the protonema-filament by means of a short stalk-cell, and rarely 
consisted of more than two green cells (Fig. 1). 
1 R. Braithwaite : British Moss Flora. London, 1887. 
2 Loc. cit., i, p. 222. 
