ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
561 
viz. : — (1) Those in which the outer teeth mostly or exclusively bend 
inwards ( Ceratodon , Barbula, Pylaisia ) ; (2) those in which they mostly or 
exclusively bend outwards ( Orthotrichum , Grimmia, Dicranum, Dicranella, 
Funaria , Fissidens ) ; (3) those in which the outer teeth have an oscil- 
lating movement on contracting and swelling (. Hypnum , Amblystegium , 
Plagiothecium , Bhyncliostegium , Brachythecium , Camptothecinm , Neckera , 
Homalia , Bryum , Mnium ). Examples of each of these groups are de- 
scribed in detail. The direction of the curvature of the teeth on an 
alteration in the moisture is determined, as in the sporange of a fern or in 
an anther-lobe, by the unequal solidity of their inner and outer surfaces. 
This property resides especially in their radial walls, which are capable 
of great swelling. 
Non-Sexual Propagation of Campylopus flexuosus.* — Hen* J. 
Familler has investigated the mode of propagation of this moss, by the 
separation of very slender small-leaved branches, which become detached 
at the slightest touch. These do not develop directly into a new moss- 
plant, but produce a protoneme on which the leafy plant arises in the 
ordinary way as a lateral outgrowth. The moss grows in swampy 
places, and is probably partially saprophytic. It rarely produces 
fructification. 
Biology and Physiology of Marchantiaceae-t — Herr Z. Kamerling 
has studied several points in the structure and development of the Mar- 
cliantiacese and allied families. 
The rhizoids with peculiar conical outgrowths on the inner side of 
the cell-wall (. Zapfclienrhizoiden ) are found in several species ( Mar - 
cliantia and Lunularia ). Rejecting the theories of previous observers as 
to the function of these rhizoids, the author believes at least one pur- 
pose of the projections to be to counteract the injurious effects of bubbles 
of vapour in hindering the circulation of water through the rhizoids. In 
accordance with this view, the development of this kind of rhizoid is 
largely correlated with the nature of the habitat of the species. The 
strongest development of the conical projections was seen in the stalk 
of the inflorescence of Preissia commutata. In Marchantia polymorplia 
they frequently have a spiral arrangement. The rhizoids spring from 
the under side of the thallus, and are protected by scales. 
The air-chambers of the Ricciese and Marchantieae are described. 
The stomates are of two kinds, according as the divisions in the mother- 
cell take place at right angles or parallel to the surface of the thallus, 
the canal-shaped stomates being the result of the latter process. The 
structure of the stomates differs in minor details in different genera. 
In reference to their habits and biology, the author classifies the 
Marchantiales under six types, viz. : — The ephemeral type ( Biccia glauca , 
Bicciocarpus natans, & c.) ; (2) the xerophytous type (Biccia lamellosa, 
Oxymitra py rami data, Targionia Tiypopliylla , &c.) ; (3) the alpine type 
( Clevia , Sauteria, Peltolepis) ; (4) the Lunularia type ( Marchantia pal- 
mata , Lunularia cruciata, Fimbriaria stahliana, &c.) ; (5) the hygrophilous 
type ( Fegatella conica, &c.) ; (6) the bog type (Marchantia polymorpha 
alone). 
* Flora, Ixxxiv. (1897) Erganzsbd., pp. 174-5 (2 figs.)- 
f Tom. cit., pp. 1-68 (3 pis.). 
