OBSERVATIONS ON TROPICAL AMERICAN AND OTHER LICHENS. I. CARROLL W. DODGE Mycologist and Professor in the Henry Shaw School of Botany of Washington University In connection with my lichen flora of Costa Rica¹ ¹ Dodge, C.W. The foliose and fruticose lichens of Costa Rica [I]. Ann. Mo. Bot.Gard. : - . 1 map. 193 ; II.Stictaceae and Peltigeraceae. Ibid. : - . 1939. I have studied many specimens from other parts of the world, mostly the American tropics. To discuss them adequately in that work would increase its size without greatly increasing its usefulness to the Costa Rican student; therefore it is proposed to include such observ- ations in this series, rather than holding them in manuscript until sufficient have accumulated to justify a monograph of a family or a flora of a region. Collemaceae