Cephalozia. 11 



Zoopsis was at first curiously misunderstood, Taylor having de- 

 scribed the stem as a frond, with crenate or sinuato-repand margins, the 

 supposed crenations being true, though minute and scale-like leaves. 

 It has also escaped the notice of all recent writers on the subject that 

 the leaves of the two original species, Z. argentea H. f. et Tayl. and Z. 

 setulosa Leitgeh, although so minute, are really bilohed ! ! In Z. argentea 

 the leaf consists (normally) of two large cells only — not placed one upon 

 the other, but laterally contiguous on a line parallel to the axis of the 

 stem ; and the two cells are connate only in their lower half, so that the 

 upper half of each projects as a hemispherical or paraboloidal lobe. In Z. 

 setulosa, however, each basal cell is tipped by another cell — slender, hooked 

 and claw-like — and the bilobed structure is manifest. These two species 

 have been found in New Zealand, Tasmania, and as far north as Java. 

 In the Amazonian Z, monodactyla the leaves are only one-lobed, and they 

 are almost exact counterparts of a half leaf of Z. setulosa, for they consist 

 of a single large truncato-conical basal cell, tipped by a much smaller 

 and slenderer unguiform. cell ; but the missing lobe is restored in the 

 bipartite $ bracts, and the cf bracts also are usually bidentate. — In all 

 the species, the postical ramification, the involucres of both sexes, the 

 monandrous cf bracts, the trigonous perianth and the 2-layered capsule, 

 are exactly as in Cephalozia. — Z. monodactyla differs from Eucejoh.mi- 

 cromera — even when the leaves of the latter shew only a single lobe — in 

 the stem being formed of only 5 longitudinal series of cells, 4 cortical 

 and 1 axial, and in the leaves consisting of but 2 (rarely of 3) cells : 

 whereas in G. micromera the stem has 6 rows of cells, and the cuneato- 

 quadrate leaves consist of about 10 cells. These are the main differ- 

 ences, and they are obviously insufiicient_ to constitute a valid generic 

 distinction.* 



In Pteropsiella the stem-leaves entirely disappear, and are replaced 

 by a broad green wing, of from 4 to 12 rows of cells, on each side of the 

 stem, exactly as in Blyttia, Metzgeria, &c., to one of which genera the 

 plant might easily be referred, were it not observed that the cladogenous 



*As those species of a genus, or otlier group, whose development is of the lowest 

 grade often resemble the young stage of the most highly-developed species ; so, in this 

 case, a mature plant of a Zoopsis is very like, in its vegetative organs, the earlier 

 stage of a Eucephalozia. (Cf. Hofmeister on the Higher Cryptogamia, t. ix, figs. 8, 9, 

 of a young plant of Cephalozia bicuspidata, where the rudimentary leaves consist of 

 only 1, 2, or 3 superposed cells, as in the fuUgrown leaves of C. Z. monodactyla. ) 



