14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 69 



TORTULA ERUBESCENS (C. M.) Broth, in Engl. & Prantl, Pflanzenfam. 



i 3 : 434, 1902 



Barbula erubcscens G M. Nuov. Giorn. Bot. Ital. 4 : 14. 1872. 

 Barbula Hildcbrandti C. M. Linnaea 40:294. 1876. 

 Barbula Leikipiae C. M. Flora 73 : 480. 1890. 

 Barbula meruensis C. M. Flora loc. cit. 

 Barbula exesa C. M. Hedwigia 38 : 103. 1899. 

 Barbula oranica C. M. Hedwigia loc. cit. 



Loc. 3,630 meters, No. 1583. This species is marked by the ex- 

 treme fragility of the lamina of the leaf, which is carried to such an 

 extreme that the whole of the leaves on a stem will frequently have 

 almost disappeared with the exception of the midrib, and it is often 

 difficult to find a leaf intact or even nearly so. The plants in the 

 above synonymy were described as separate species, chiefly on the 

 ground of their geographical position. One or two characters noted 

 by C. Miiller as apparently constituting distinctions are quite value- 

 less. These are : A certain diversity in the size of the upper cells, 

 the direction of the leaves when moist, whether erect-patent or some- 

 what recurved ; the outline of the leaf, the degree of recurving of 

 the margin, and the smoothness or roughness of the nerve at the 

 back near the apex. Nearly all these characters show an equal 

 degree of variation, within the limits of a single species, in allied 

 European species of Syntrichia, and I should have been inclined to 

 doubt, a priori, their validity. Apart from this, I have examined 

 specimens of most of them, including the originals of B. erubescens 

 and B. Hildebrandti, specimens of B. meruensis determined by 

 Brotherus, and South African plants corresponding no doubt to one 

 or both of the two species cited last in the synonymy. In all of these 

 I find the above characters eminently variable. B. Hildebrandti, for 

 example, has on the same specimen, and sometimes on the same stem, 

 leaves varying from erect-patent to patent and slightly recurved, the 

 apex broadly rounded or only subobtuse, the nerve rough at the 

 back above or quite smooth. Similar variations occur in the other 

 characters mentioned above, in some at least of these plants, and I 

 have no question at all that they all belong to one rather remarkable 

 and not on the whole very variable type. The nerve is excurrent in 

 a very short red mucro, which may be either stout and obtuse or 

 tipped with a very short, fine, paler point or apiculus. 



TORTULA CAVALLI Negri, Annal. di Bot. 7: 164. 1908 



Loc. 3,630 meters, Nos. 1358 (c. fr.), 1542 (c. fr.), 1572 (c. fr.), 

 1545 (c. fr.), 1566 (c. fr.), 1579, 1596, 1597. Loc. 4,200 meters, 

 No. 1656 (c. fr.). 



