CHILEAN SPECIES OF METZGERIA. 319 



Apollo Bay," and is presumably the first, of the specimens originally 

 listed. It may therefore be regarded as the type of the species. This 

 specimen is unfortunately fragmentary and is nearly destitute of 

 sexual branches, the few present being poorly developed. The thallus 

 is almost plane, and the costa shows the four rows of cortical cells — 

 two dorsal and two ventral — as called for in the description (Fig. 

 10, C). 



The alar cells are in most regions rather large, measuring mostly 

 65-70 fx in length by 50-55 11 in width, but cells as short as 55 lx (or 

 even slightly shorter) are not infrequent and may occupy considerable 

 areas in thalli where most of the cells show the higher measurements. 

 It will be seen that these figures are appreciably higher than those of 

 the writer for typical M. hamata. Trigones are scarcely discernible. 

 When the marginal hairs are abundant they occur in pairs, slightly 

 displaced to the ventral surface, and there may be a pair between every 

 two marginal cells ; when the marginal hairs are scattered they usually 

 occur singly, and long stretches of the thallus may be wholly free from 

 hairs. The costal hairs tend to be less numerous than the marginal 

 hairs but are sometimes crowded. At their best development the 

 hairs are long and flexuous, attaining a length of 0.3-0.4 mm. 



Several of the New Zealand specimens in the Mitten Herbarium 

 were collected by Colenso but Xo. 279 is not present. There is, how- 

 ever, in the herbarium of the New York Botanical Garden, a specimen 

 collected by Colenso and received from Kew, that closely agrees with 

 the Apollo Bay specimen. This bears the number 1100. It has a 

 slightly convex thallus, the margins being subrevolute, and the margi- 

 nal hairs in exceptional instances arise in three's or even in four's. 

 The alar cells of this specimen average about 70 X 55 lx (Fig. 10, D). 



If these two specimens were the only ones to be considered it might 

 appear as if M. nitida could be separated from M. hamata by its larger 

 leaf-cells. Other specimens, however, from Australia and New Zea- 

 land, show that this distinction is inconstant. Although agreeing with 

 the Apollo Bay specimen and No. 1100 in other respects these speci- 

 mens have distinctly smaller cells. In one Australian specimen, col- 

 lected by Hartmann, for example, they average about 49 X 40 ll ; in 

 another, collected by Lucas, about 54 X 40 lx; in a New Zealand 

 specimen without the collector's name, about 42 X 36 lx, etc. It is 

 clear, therefore, that the distinction in the size of the cells breaks down, 

 and since no other more important and constant distinction has been 

 brought forward, the two species are evidently identical. 



Stephani's M. australis, which he at one time regarded as a synonym 



