390 A. W. Evans— Haioaiian Hepaticfje of the Tribe Jubuloidece. 



constant throughout the group. The leaves are complicate-bilobed,* 

 the antical lobes being the larger and incubous in their arrangement, 

 while the smaller postical lobes or " lobules " are usually wholly or 

 partially inflated and serve as water-sacs. Except in the two genera 

 Cololejeiinea and Metzgeriopsis^ underleaves are always present; 

 usually there is only one underleaf developed for each pair of side- 

 leaves, but in the genera Diplasiolejeunea and Cohirolejeunea there 

 is an underleaf for every side-leaf, a peculiarity found nowhere else 

 among the Hepaticre. The branches, sexual as well as vegetative, 

 are invariably lateral. The female inflorescence, which is of course 

 always terminal, is sometimes borne on the main stem or on a prin- 

 cipal branch, sometimes on a short, special branch. The number of 

 archegonia is always small, almost never exceeding four. The peri- 

 chsetial bracts, like the leaves, are complicate-bilobed, but they are 

 usually larger and their lobulesf are never inflated; the bracteolesj 

 likewise are larger than ordinary underleaves. A perianth is always 

 present and is entirely free from the bracts; it is of the hypogonian- 

 thous type, but its keels are not always distinct; in the upper part, it 

 is abruptly contracted into a more or less distinct beak with a small 

 opening, and it becomes lacerated when the capsule is extruded. The 

 calyptra is free. The antheridia are borne, usually in pairs, in the 

 axils of inflated, complicate-bilobed, perigonial bracts, whose lobes 

 are subequal in size; these bracts are imbricated, often very densely 

 so, and occur in clusters of from two to manj^ pairs, sometimes in 

 the course of an ordinary branch, sometimes on a short specialized 

 branch. The corresponding bracteoles are usually smaller than 

 ordinary underleaves and are often absent from the upper part or 

 even from the whole extent of the antheridial spike. The rhizoids 

 of the Jubuloideae are sometimes abundant and sometimes very 

 scanty. They are borne in clusters, each cluster arising from the 

 lower surface of an underleaf, close to the base. In the genus Colo- 

 lejeiinea, the clusters of rhizoids are found on the postical surface 

 of the axis, in the position where underleaves Avould naturally be 

 expec-ted. 



The sporophyte, although so much simpler than the gametophyte, 

 affords important and constant characters. The stalk, instead of 



* A single exception is found in the nionotypic genus Myriocolea Spruce, of 

 South America, in which no lobule is developed. 



f In certain genera the lobules are small and indistinct and are sometimes 

 entirely obsolete. 



X The bracteoles are absent in the genera without underleaves; they seem to be 

 absent also in most species of Colurolejeunea. 



