(120) 
As regards the thallus, Acarospora ranks with the other subfoliaceous 
divisions of Lecanora; being yet distinguishable from them no less by 
the irregularity of the spores than (much as Alphoplacium from Squama- 
ria) by the smaller spermatia. In all about twenty more or less marked 
forms have been described, but the limits of Z. cervina are understood 
as differently as those of ZL. cinerea in the last group, and the number of 
probable species may be very much less. Almost all are northern, and 
European; of which the more conspicuous ones have been recognized 
here. Nylander reckons (Enum. Gén. p. 112) three austral species, one of 
which, found also (Nyl.1.¢.) in tropical America, extends within our limits. 
L. molybdina (Wahl.) Scheer., heretofore confined, on this continent, 
to the arctic zone, has recently been detected at Tadousac in Canada 
(Alr. Drummond).——ZL. chlorophana (Wahl.) Ach., is also an arctic 
lichen, occurring in Greenland (J. Vahl, fide Th. Fr. ]. ¢.) but Mr. Wright 
collected it in the Organ mountains, Texas; and it has since been found 
in Utah (Mr. 8. Watson), in Alpine co., California (Dr. Lapham), and on 
the coast of California (Mr. Bolander).——The Chilian L. xanthophana, 
Nyl. Enum. Gén. (named by the present writer, the same year, L. chry- 
Sops, Suppl. 1, but previously described, under another name, by the 
eminent author first cited) collected in Texas and Mexico by Wright, has 
since occurred in Missouri and Kansas (E. Hall) in the Rocky Mountains 
(Dr. Hayden) in South Carolina (Mr. Ravenel) and recently, even in New 
Jersey (Alr. Austin).——Closely approximate to the last is the terricoline 
L. Schleicheri (Ach.) Nyl., found in the alpine districts of the Rocky 
Mountains (Dr. Hayden; Mr. E. Hall) as on the coast of California (Ar. 
Bolander).——L. cervina (Pers.) Sommerf., is, in one form or other, all 
but everywhere diffused in North America; its finer forms are however 
rare. I have a, glaucocarpa, Sommerf. (taken by Fries also for the type 
of the species) only from the lime-rocks of Vermont (Mr. Frost).——The 
var. 8, squamatlosa, Fr. (L. cervina, «, Nyl. Scand.) extends to other than 
calcareous rocks, and has occurred on granite in Vermont (Mr. Frost) as 
in Greenland (J. Vahl, in Th. Fr. 1. ¢.) and in the finest lusuriance, on 
granitic rocks, in the Yosemite valley, California, and in Nevada (Mr. 
Bolander).——An infertile lichen (designable as Z. thamnina) which I 
cannot but associate with the other Californian forms of 7, proves yet to 
be really made up of crowded trunks (as in L. thamnoplaca of the same 
region, and Lecidea conglomerata) the longest of these trunks, which 
branch irregularly above, and are there flattened into the brown squam- 
ules constituting the outer crust, having a height of 7™™- This remarka- 
ble overgrowth has not been described by European writers, as occurring 
in their forms of the species before us;! it looks at least possible however 
1 Jt is yet observable that Fries describes (Z. £. p. 127) the squamules of 
L. cervina as sub-peltate; and in this view the analogy of L. thamnina with 
L. rubina, vy. complicata, Anz. (Lich. Langob.) is evident. 
