INTRODUCTION TO CRYPTOGAMIC BOTANY. 453 



iu St. Helena. Blyttia is distinguished by a general and proper 

 involucre. The male organs are accompanied by scattered or 

 crowded toothed perigonial scales. The elaters are at first at- 

 tached to the inner surface of the valves, and at length deciduous. 

 Blyttia Lyellii is one of our most interesting Jungermannice. 

 B. Phyllanthus resembles in habit Syviphyogyna subsimplex, 

 but the fruit is very different. This latter is, however, separated 

 by Mitten under the name of Podomitrium, on account of the 

 ventral involucre and pedicellate male spikes. In Blyttia, the 

 anthers are dorsal and imbedded on each side of the nerve. 

 Like >S'. subsimplex, Podomitrium grows on tree-ferns. 



7. CoDONiEja, Dumort. 



Fronds pinnatifid, the divisions leaf-shaped or lamellate 

 above ; perianth large, campanulate. 



497. This tribe conducts us by slow degrees through Fos- 

 sombronia, to the truly leafy Jungermannio}, which form 

 the vast mass of the order. Zoopsia, however, which occurs in 

 several places in the southern hemisphere, makes no approach 

 to the more leafy JuTigermannice. It is remarkable for 

 its silvery, often cylindrical, rigid frond, resembling some 

 zoophyte, without any trace of a border, and consisting of 

 large cells, built round a central axis. Petalophyllum (Fig. 

 95, a) has fronds with gill-like folds above. P. Ralfsii is a 

 most interesting species, and remarkable for its sporangium 

 being valveless. The sporangium rises from a broad bell- 

 shaped perianth ; its surface is curiously tesselated in conse- 

 quence of the outer coat being less, extensible than the inner. 

 The spores are reticulated and resemble those of a truffle. 

 The elaters have two and sometimes three spires, and are 

 often forked. P. Preissii is an Australian species. In this 

 the folds sometimes assume the form of leaves, especially 

 on the young shoots. Ando-ocryphia (Fig. 95, e) has one 

 Brazilian and one antarctic species. Like Fossombronia, it 

 has distinct distichous succubous leaflets, but differs in its regu- 

 larly quadrivalve sporangium, bilobed perianth, and immersed 

 antheridia. F. pusilla is a widely distributed species, occurring 

 both in the north and south hemispheres; the others are all 

 species of warmer climates than our own. 



