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The tropical lichen owes its name to the often warted thallus; but this 
difference at length disappears. In the f. chlorites (Lecidea, Tuck. in litt. 
Nyl. in Prodr. Fl. N. Gran. p. 66) these warts are sulphur-coloured 
within, and the plant (Wright Lich. Cub. n. 229) is also distinguishable 
by smaller apothecia. It has been detected in southern Alabama (Mr. 
Beaumont). 
7, pachycheilum: apotheciis rufo-fuscis (nigrescentibus) margine tur- 
gidulo pallido; sporis 2-408, 4-8-locularibus, curvulis. Lecidea pachy- 
cheila, Tuck. Obs. Lich. 1. ¢. 6, p. 281, & in Wright Lich. Cub. n. 230. Nyl. 
l.c. p. 67. The pale exciple, and shorter, often sickle-shaped spores, 
occurring in 2s and 4s in the thekes, distinguish this lichen, which has 
been found on the seaboard of South Carolina (Mr. Ravenel) in southern 
Alabama (Mr. Beaumont) in Mississippi (Dr. Veitch) and in Louisiana 
(Hale). Dr. Nylander compares it with the f. chlorites of the preceding 
variety, but it also closely approaches the next. 
6, amplificans: apotheciis ‘pallide spadiceo-testaceis’ (nigrescentibus) 
margine turgido pallido ; sporis 4-8"*, 9-11—locularibus. Lecidea ampli- 
Jicans, Nyl. in Prodr. Fl. N. Gran. p. 67, & in Herb. Lindig, n. 2812. So 
far as my specimens go, this New Granada lichen appears probably the 
finest condition of the species. It is readily comparable with the last 
however, and through that with Z. tuberculosa, Fée, with which it also 
agrees in its warted thallus. 
H. Domingense (Pers.) (Lecanora, Ach., Fée. Parmelia gyrosa, Mont. 
Heterothecium, Flot.).— Trunks in the low country of South Carolina 
(Mr. Ravenel) and Louisiana (Hale). From this, H. vulpinwm, Tuckerm. 
(Obs. Lich. 1. c. 6, p. 281, sub Lecid. Wright Lich. Cub. n. 233) as respects 
all more obvious features, whether of thallus or apothecia (though the 
last are smaller) should scarcely be separable; but the larger spores are 
muriform-multilocular, as characteristical in the next section. Very dif- 
ferent inferences may be drawn from this. One may well be that the 
weight of the evidence favours placing the lichen with H. Domingense, 
notwithstanding the great difference in the spores; its relation to the 
other being not dissimilar to that of Arthonia cyrtodes f, already cited, 
toa: and that thus we have a new instance in the argument against 
allowing more than subordinate value to the distinction of the muriform 
spore generally, from the antecedent plurilocular; not without interest, 
especially in such genera as Thelotrema, Graphis, and Pyrenula.——In 
H. aureolum, Tuckerm. (Lecidea, Tuck. l.c. Nyl. in Prodr. Fl. N. Gran. 
p. 68) we have, on the other hand, dissimilarity in general habit from 
H. Domingense, with similarity in the spores. These small-spored species 
of Heterothecium make less applicable the original name of the genus 
(Megalospora) but are by no means separable from it. But the final mod- 
ification of the type of spore, of which Bombyliospora expresses a stage, 
is the muriform-multilocular: characterizing (in the present group of 
Lichens) Heterothecium, Mass., and Lopadiwm, Koerb.; and exactly cor- 
