The Collemaceae of Ohio 
57 
On rocks and on trunks of trees. Examined from areas about Colum¬ 
bus, Sugar Grove, Peebles, and Eaton. 
4. Leptogium chloromelum (Sw.) Nyl. Syn. Lich. j: 128. 1858. 
Lichen chloromelos Sw. El. Ind. Occ. y.' 1892. 1808. 
Transforming the algal-host colony into a middle-sized, suborbicular 
or irregular, thin body, which is 2 to 7 cm. across and 50 to 185 mic. 
thick, with sometimes scattered, usually isidioid-granulate, frequently 
imbricate, ascending lobes, with crisped, undulate, or isidioid-lobulate 
margins, with the upper surface lead-colored varying toward green or 
olivaceous, with the lower surface scarcely lighter colored, and with the 
algal chains somewhat evenly distributed; medulla of densely, uniformly, 
and variously disposed hyphse, which are 2 to 5 mic. wide, sometimes 
plectenchymatoid in part or throughout; cortex rather poorly developed 
and not always continuous, the cells of the upper cortex 7 to 16 mic. long 
and 4.5 to 12 mic. wide, those of the lower cortex scarcely differing in 
size; cortex several cells in thickness around and usually below the 
apothecia; rhizoids often seen in sections, especially under the apothecia; 
apothecia commonly present and often numerous, small to middle-sized, 
sessile, 0.5 to 1.5 mm. in diameter; disk slightly concave to slightly con¬ 
vex, brown, surrounded by a granulate, entire or irregular thalloid mar¬ 
gin, which may extend above it; exciple and hypothecium of interwoven 
hyphge, but both structures wholly or in part plectenchymatoid, the latter 
80 to 105 mic. thick; hymenium 105 to 155 mic. thick; spores ovoid to 
ellipsoid-pointed, longitudinally 4-celled, transversely 2-celled, 15 to 30 
mic. long and 8 to 13 mic. wide. See Eigs. 4, 19, and 22. 
Widely distributed in the state, but infrequent. On rocks and tree 
trunks. Examined from areas about Springfield, Scipio, Oxford, Paint, 
Mineral Springs, and Peebles. 
5. Leptogium plectenchymum sp. nov. 
Transforming the algal-host colony into a small or middle-sized, 
suborbicular or irregular body, which is 0.8 to 7 cm. across, 35 to 110 
mic. thick, and somewhat loosely adnate, with ascending and often imbri¬ 
cated lobes, with entire or irregular, often minutely lobulate margins, 
with the upper surface lead-colored, with the lower surface somewhat 
lighter colored, and with the algal chains somewhat evenly distributed; 
medulla of densely and uniformly distributed, vertically and variously 
disposed hyphse, which are 3 to 5 mic. wide; cells of the upper cortex 
9 to 19 mic. long and 5 to 14 mic. wide, those of the lower cortex some- 
