COLENSO's NEW-ZEALAND HEPATIC^). 279 



was to be expected as the specimen will allow, particularly of 

 sexual organs. 



(5) Isotachis. — This genus, founded by Mitten, was revised 

 by Gottsche in his ' Prodromus Florae Novo-Granat.' (Ann. Sc. 

 Nat. ser. 5, i. (1864), pp. 120-125), where he describes the apex 

 of the perianth as being " veiled by dentate scales " (" apice squa- 

 mulis dentatis obvelatum"). A few pages later on he says of 

 Isotachis serrulata more distinctly : u ore squamulis dentatis 

 cxterne accretis obvelato." In the German text, cited from 

 Gottsche andEabenhorst, ' Hepaticae exsiccatae ' No. 272, he speaks 

 of the young pistillidia as " surrounded by a ring of small involucral 

 scales, around which the perianth is formed; while the calyptra 

 is taking up the pistillidia, the perianth carries up the scales, so 

 that after full development they are found externe accretse." 



In the diagnosis of Isotachis Lindigiana he furthermore states 

 " externe squamis minoribus obsesso," while in the detailed de- 

 scription following the " I? eri&nthium facie interna multas excres- 

 centias monstrans " is described. This repeated contradiction is 

 nowhere explained. 



If thin longitudinal sections of a well-developed perianth of 

 Isotachis are made, we find them to consist of several layers of 

 cells ; the innermost layer, which is shorter, can be traced down to 

 the base, and runs out into a variable number of free lacinice. 



The outer layer forms what we heretofore have been used to 

 call the perianth ; it is longer than the internal layer, the apex of 

 which is perfectly hidden and cannot be seen from above ; the 

 apex of the so-called perianth is split into similar irregular 

 laciniae, the outside smooth. This is what I have found in dif- 

 ferent species of Isotachis. 



"We have been used heretofore to call " perianth " the inner- 

 most concrete bracts surrounding the pistillidia of Hepaticae ; we 

 call it so in Nardia scalaris and in Sarcoscyphus, both of which 

 have short immersed perianths, embraced by much longer bracts, 

 to which they are firmly connate, forming thereby a more or less 

 fleshy cup ; only the uppermost part of these perianths is free, 

 and commonly split into a number of lobes. 



Taking this analogy, we are compelled to call the innermost 

 layer of cells in the perianth of Isotachis "perianth" the outer 

 layers " bracts*' which are longer and connate to the perianth, of 

 which only the apex is free, exactly as in Nardia and Sarcoscyphus. 



