This is an authorized facsimile

printed by microfilm/xerography on acid-free paper

in 1985 by

UNIVERSITY MICROFILMS INTERNATIONAL

Ann Arbor, Michigan, U.S.A.

ASA GRAY,

FISHER PROFESSOR OF NATURAL HISTORY (BOTANT) IN

HARVARD UNIVERSITY.

NEW YORK:

D. APPLETON AND COMPANY,

540 & 551 BROADWAY.

Grad UGL

QH

367

.G77

1877a Behr