408 A. W. Evans— Haxoaiian Hepaticm of the Tribe Jubuloidece. 



narj^ branches; the bracts are less closely imbricated, sometimes 

 scarcely touching, and the branch sometimes bears small unmodified 

 leaves beyond the bracts; the bracts have the same texture as ordi- 

 nary leaves and are not delicate as in J. HkUchinsioe; the ordinary 

 leaf-cells have slightly thicker walls and are more elongated in the 

 middle and toward the base of the lobe. 



Subtribe II. LEJEUNEE^. 



The generic limits of the forms included in the Lejeuneese have 

 been subject to considerable discussion, and the opinions of hepati- 

 cologists are still somewhat diverse concerning them. The old 

 genus Lejeimia, as first proposed by Mile. Libert* nearly eighty 

 years ago, was made up of the two European species, X. serpyllifolia 

 and L. (now Cololejeunea) calcarea. In 1831, Dumortierf added to 

 the genus the European species, caluptrifolia, hamatifolia and mimi- 

 tissima, and in 1835, J made a few more additions, mainly of tropical 

 species, at the same time separating L. calyptrifolia as the type of 

 a distinct genus, Colura. A few years afterwards, Nees von Esen- 

 beck§ also recognized the genus Lejeunea, placing in it the same 

 European species as Dumortier. 



The publication of the Synopsis Hepaticarum in the next decade 

 brought into the genus an immense number of exotic species, manj^ 

 of which had been pi-eviously described under the convenient old 

 generic name, Jungerinannia. In this way the number of known 

 species of Lejeunea was increased to nearly three hundred. At the 

 same time the authors of the Synopsis recognized or j^roposed the 

 closely related genera Sryopteris, Thysananthus, Ptychanthus and 

 Phragtnicoina\ which were made up almost entirely of extra-Euro- 

 pean forms. The characters assigned to these genera were in some 

 cases both vague and false, but they were made use of by authors in a 

 rather blind way, until the publication of Spruce's important work in 

 1884. This author jDointed out the untrustworthy and artificial charac- 

 ters of certain of the Synopsis genera and proceeded to combine, in the 

 single, much-embracing genus Lejeunea, all those Jubuloidese which 

 are constantly monogynous. He then divided his genus into thirty- 

 seven divisions, most of which are natural and well-defined. These 



* Ann. Gen. des Sci. Phys. (Brux.) vi, 373. 1820. 



f Sylloge Jungermaun. 32. 



\ Receiiil d'obs. sur les Jung. 11. 



§ NatnrgeschicMe der europ. Lebermoose, iii, 255. 1888. 



II First proposed by Dumortier for the European P. Mackaii (Hook.) Dum. 



