452 PLAGIOCHILA. 
kindness of M. Husnot, is constantly radicellose. The branches tend to 
become geniculate, and at the geniculations shortish pale radicles are 
developed, sometimes extending nearly to the apex of the branch. The 
Javan Pl. abietina N. puts forth radicles on the decurved attenuated 
apex of certain branches; so does the Nepalian Pl. semidecurrens L. et L. 
In a few species where the ascending apex of the caudex passes insensibly 
into a stem, the radicles may be continued a long way up the latter. In 
the European Pl. interrupta I find a prostrate stem, radicellose and small- 
leaved at the base, for a short distance, then slightly assurgent and 
branched, with the branches usually bare of radicles except when the 
decurving apices bring them into contact with the matrix, when they 
may emit a tuft of radicles. ‘lhe feature is not more marked than in 
Pl. tenuis; and.if, along with the monoicous inflorescence and the some- 
what flatter leaves, it be held sufficient to separate the species from normal 
Plagiochila, it can only be as a subgenus (Pedinophyllum Lindberg), but 
never as a member of the verticillate-leaved Leioscyphus, with which 
some authors have united it. 
Some plants, however, with distinctly rooting stems, which have been 
described as Plagiochilz, are plainly members of other genera. Pl. luxa 
L. et Lindn. Sp. Hep. t. 18, which I have gathered with ¢ flowers in 
the Andes, is a Tylimanthus, allied to T. saccatus (Hook. Muse. Exot. t. 6) 
Mitt.—To the same genus possibly belong Pl. amplexifolia Hpe. and 
Pl. comata, N., known only in a barren state—Pl. variegata Lindenb. Sp. 
Hep. t. 33, is a species of Syzygiella (nob. in Journ, Bot. 1876), allied to 
S. perfoliata (Sw.).* 
The branches of Plagiochile are uniformly lateral, springing from the 
leaf-axils, usually towards their postical angle, but sometimes (especially 
in the pinnately-branched species) adjacent to the middle of their base. 
Gemmz are rarely produced on the leaves of Plagiochile in the 
Amazonian plain and the slopes of the Andes, where there is almost 
perennial moisture ; but when trees and shrubs are cut down for a new 
plantation, and are allowed to lie until dry enough to be burnt, the 
mosses on their trunks and branches—no longer protected from the sun’s 
scorching rays by a leafy canopy—begin to shrivel up. Then the leaves 
of the Plagiochile disintegrate at the margin ; the loosened cells hang 
awhile in little masses, then fall away and are dispersed—some to renew 
their growth as distinct individuals. 
The marginal teeth or cilia, which are so marked a feature of the large 
leaves of Plagiochile, are uniformly acute, ending in a single sharp- 
pointed conical cell; and whenever a blunt tooth is seen it indicates 
either malformation or disease: the latter often induced by unwonted 
drought, or abstraction of essential shade, such as I have just described. 
Thus I am pretty certain that the figure of Pl. swrinamensis Sande-Lac., 
in Hep. Jav. Suppl. t. 20, has been made from a plant picked off a fallen 
tree in some new clearing in Dutch Guiana, which is indicated by the 
ragged edge and broken teeth of the leaves, such as exist in the perfect 
state of no Plagiochila. 
Propagula, in the shape of leaf-suckers—minute branchlets springing 
from the surface of the leaves, and each based on a single cellule—are 
frequent enough, and indicate a degree of moisture suflicient to check 
* Two Javan species, Pl. costata N. Sp. Hep. t. 26, and Pl. ciliolata N. 1. ¢. t. 
30, with large connate ovate ciliated underleaves and trialate perianths, are 
plainly nearer Lophocolea than Plagiochila, and should probably constitute the 
type of a new genus. 
