72 PLANTS OF RHODE ISLAND. 
PELTIGERA, (Willd.) Fee. 
1. aphthosa, (L.) Hoffm. On ground and on rocks. — 
2. horizontalis, (L.) Hoffm. On wet rocks. 
3. polydactyla, (Neck.) Hoffm. On ground and on rocks. 
4, rufescens, (Neck.) Hoffm. On ground, on trunks and on rocks. 
5. canina, (L.) Hoffm. On ground and roots of trees. 
PHYSMA, Mass. 
luridum, Mont. On rocks and fences. 
PANNARIA, (Delis.) Tuckerm. 
1. microphylla, (Sw.) Delis. On rocks and trees. 
2. tryptophylla, (Ach.) Mass. On rocks. 
HPHEBH, Fr., Born. 
pubescens, Fr. On rocks. 
OMPHALARIA, Dur. & Mont. 
phyllisca, (Wahl.) Tuckerm. On rocks. 
COLLEMA, Hoffm., Fries. 
1. pycnocarpum, Nyl. On tree trunks. 
2. leptaleum, Tuckerm. On trees. 
3. flaccidum, Ach. On rocks. 
4. nigrescens, (Huds.) Ach. On trees. 
5. ryssoleum, Tuckerm. On rocks. 
LEPTOGIUM, Fr., Nyl. 
1. lacerum, (Sw.) Fr. On wet rocks. 
2. pulchellum, (Ach.) Nyl. On base of trees and rocks. 
3. Tremelloides, (L.f.) Fr. On rocks and trees in wet places. 
4. myochroum, (Ehrb.) Tuckerm. In similar positions. 
a. saturninum, Schaer. Onrocks and trees. 
PLACODIUM, (D.C.) Naeg. & Hoppe. 
1. cinnabarrinum, (Ach.) Anz. On rocks. 
2. microphyllinum, Tuckerm. On old fences. 
3. aurantiacum, (Lightf.)N.&H. On trees and dead wood. 
4. cerinum, (Hedw.) b. sideritis, Tuckerm. On rocks. 
5. ferrugineum, (Huds.) Hoppe. On fences and rocks. 
b. Pollinii. On trees, especially Juniperus. 
5. vitellinum, (Ehrb.) N. & H. On rocks and fences. 
LECANORA, Ach., Tuckerm. 
1. rubina, (Vill.) Ach. On rocks. 
. muralis, (Schreb.) Schaer. a. saxicola. On rocks. 
3. pallida, (Schreb.) Schaer. On trees and dead wood. 
c. angulosa, Hoffm. On rail fences. 
