548 DR. LINDSAY ON NEW-ZEALAND LICHENS. 
coloured, the thecæ 1-spored, the spores figure-8-shaped, 1-septate, colourless, broadly 
oblong-oval, *0040" to 0050" long, 0016" broad. 
Sp. 9. L. erossa, Pers. (Figs. 13-15.) 
On trunks of living trees, Greenisland bush, Stoney-hill bush, and East Taeri bush; 
athalline, on dry, weathered, dead stems and roots of grasses and carices, matted in tufts, 
Forbury cliffs, Otago: W. L. L. Next to L. marginiflexa, one of the commonest and 
most prominent corticolous Lecidew of the Greenisland district of Otago. 
Spores (fig. 13 d, e) somewhat variable in form and size, generally broadly ellipsoid or 
subspherical, sometimes oval or pyriform; colourless, l-septate, septum not always 
median ; :0009" to *0012" long, 00045” to -0005^ broad. Thecæ (b) 8-spored, 0045" — 
. long, :0012" to -0015" broad, beautiful blue with iodine. Paraphyses (a) subdiserete, 
delicate, filiform ; tips tuberculiform, obscured by much dark, brownish-black, granular 
colouring-matter. Hymenium (b, c) beautiful blue with iodine; the coloration extend- 
ing from, and deepest at, the tips of the paraphyses; in section very distinct and in- 
structive, one of the best in which to study the anatomy of the apothecium of the genus 
Lecidea. Both hypothecium and epithecium dark brown. Apothecia sometimes white- 
pruinose. "Thallus sometimes thick and coralloid or isidiiform, resembling certain forms 
(muscicolous and corticolous) of Lecanora parella and L. tartarea, or, it may be, thin, or 
altogether (apparently) absent. In general external characters the plant has a re 
semblance to various other Lecidee, equally or more common at home and abroad, 
including especially L. diseiformis, L. parasema, L. marginiflexa, and L. premnea—so 
much so that, in the Hookerian and other herbaria, there is great confusion between 
these species, which in all cases require microscopical examination for their discrimina- 
tion. Fortunately their spores at once distinguish them. 
À specimen in herbarium Kew (fig. 15) [sub nom. L. premnea, Ach., on bark, Forfar 
(Drummond)] has colourless, oval-oblong, 1-septate spores, *00083" to 0010” long, 0005” 
broad, and thecæ -005” long, :0018" broad. Few British species have handsomer spores 
or thecæ. A specimen from the United States of America (Green, No. 71) is labelled 
L. parasema, while others are erroneously labelled Z. disciformis, and vice versd. In a 
specimen in my herbarium from Rio Janeiro (fig. 14) [Henry Paul, 1846], the thecæ (a) 
are subsaccate, blue with iodine, developing only two spores—a condition approaching 
the 1-spored L. marginiflexa. The loculi of the spores (5, c) are sometimes pale brownish 
yellow ; under iodine, as is generally the case with the colourless spores of lichens, 
they acquire a deep yellow tint, while their protoplasm or contents assume à subgranular 
appearance (d). 
Sp. 10. L. prscrronurs, Fr., var. albula, Nyl. 
North Island, on limestone (Colenso): in herbarium Kew. Apothecia scattered on à 
mealy white thallus,—the whole plant resembling certain forms of L. albo-atra, Hffm. 
On columnar basalt, Greenisland bluff, Otago, associated with Z. lenticularis, Ach. 
(Nyl. L. N. Z. 257), is a difform condition, which I refer to this species, or to some 
the allied species, such as L. myriocarpa and L. stellulata (which, I think, should be 
considered mere forms or varieties of Z, diseiformis). The spores (fig. 16) have all the 
