A. W. Eoans — UmoaiUm Hepaticce of the Tribe Jahaloidem. 425 



The determination of this extremely variable species is based on a 

 part of Austin's original material, which I owe to the kindness of 

 iMr. Pearson. These plants are much elongated and sparingly 

 branched and very few of them show any signs of inflorescence ; in 

 fact, I have been able to find only two perianths upon them, each of 

 which is subtended by a single innovation. Similar elongated forms 

 are found among Mr. Cooke's specimens, and these, like the type, 

 are almost invariably sterile. A few of them, however, show unfer- 

 tilized female flowers which are innovant, sometimes on only one side, 

 but usually on both. The more common form of the species appears 

 somewhat different from these elongated conditions : the stems are 

 shorter and are almost always fruiting, and the female flowers are 

 innovant on both sides, giving the plants thereby a forked appear- 

 ance. Even here, however, a one-sided innovation is very frequent. 

 Although these two extreme forms appear so unlike, they are con- 

 nected with each other by numerous intermediate conditions. The}' 

 also agree so perfectly in their leaves with their apical teeth and 

 decurrent keels, in their leaf-cells, in their underleaves, and in their 

 floral leaves and perianths, that it is impossible to draw a line 

 between them. 



The t3fpe-specimen of Angstrom's Lejeunea aliena, kindly sent me 

 b}- Professor ^Nathorst, is very similar to that of Phragmlcoma 

 elongata, while the type of Dleranolejeunea Didericiana is more 

 like the usual form of the species. Herr Stephani has recently pub- 

 lished, as Brachiolejeunea aplcalata n. sp ,* a plant collected by 

 Mr. Heller on Oahu. The type of this species appears to be inac- 

 cessible : there are no specimens so named among Mr. Heller's plants 

 in New York, and Herr Stephani's own specimens seem to have been 

 mislaid. The author, however, has had the kindness to send me a 

 drawing made from the original material, which shows a leaf, an 

 underleaf, and a perianth with its involucre. Judging from this 

 drawing and from the published description, the plant is very close 

 to Thysanantkus elonc/atus and may be a form of it, as the differ- 

 ences brought forward could easily be accounted for by the verv 

 great variability of the species. The matter, however, must be left 

 in doubt for the present. 



The widely distributed Thysanaiithus frulicosus Lindenb. & 

 Gottsche differs from T. elongatvs in its vittate leaves and in the 

 much sharper and more numerous teeth on its leaves, underleaves, 

 bracts and perianth, as well as in the different shape of the last named 



* Bull, de I'Herb. Boissier, v, 846. 1897. 



