CHILEAN SPECIES OF METZGERIA. 291 



and ventral alar hairs, while it differs from M.furcata in having paired 

 marginal hairs. When strongly pubescent it resembles M. corralensis 

 rather markedly but is distinguished by the more definite structure 

 of the costa, by the occurrence of the marginal hairs in divaricate 

 pairs, and by the marginal gemmae. 



5. Metzgeria patagonica Steph. 

 Metzgeria patagonica Steph. Bull. Herb. Boissier 7: 940. 1899. 



Specimens examined: Newton Island, May, 1896, Dusen 24 (M., 

 U., Type). 



The following additional station may be cited from the literature: 

 Escapada Island, Skyring, Skottsberg (24, p. 11). 



According to the original description of this well-marked species 

 the wings of the thallus are strongly decurved and often revolute, but 

 a supplementary note adds that the specimens are "etiolated" and 

 that the normal structure is to be found only on the younger " inno- 

 vations." In the material studied by the writer most of the thalli are 

 perfectly plane and only a few of the branches show revolute margins. 

 At the same time the plane thalli can hardly be regarded as abnormal ; 

 they do not present the appearance of being etiolated, and the pres- 

 ence of female branches in some abundance shows that the plants are 

 by no means in a juvenile stage of development. The soluble yellow 

 substance, to which Stephani calls attention in a later paper (20, p. 20), 

 is very much in evidence when the specimens are soaked in water. 



The thalli of M. patagonica are pale green, often deeply tinged with 

 yellow, and grow in depressed mats. The width is mostly 1-1.5 mm. 

 and the length may be as much as 3 cm. Measured in cells the wings 

 are usually fifteen to twenty-five cells across. Although ventral 

 branching sometimes occurs, dichotomous branching is far more com- 

 mon, the successive forks being mostly 1-5 mm. part. 



Hairs are rarely abundant and many regions are nearly or quite free 

 from them. The marginal hairs are straight and seem to be invariably 

 borne singly. They are usually slightly displaced to the ventral sur- 

 face, tending to extend at right angles to the wings, but they may be 

 truly marginal and lie in the same plane as the wings. The hairs are 

 about 10 /x in diameter and rather short, the length being usually 

 only 0.1-0.12 mm. Although the wings are naked the costa some- 

 times bears loose and scattered clusters of hairs, essentially like the 

 marginal hairs but sometimes a trifle longer. Apparently in either 



