EXPLANATION OF PLATES 
All of the figures, unless otherwise noted, are from herbarium ma- 
terial, photographed in natural size by the author. Though it has not 
been possible always to do so, an effort has been made to include in 
each illustration the lower part of a basal internode so as to show the 
presence or absence of cataphyls; and except for types of the older 
species a representative specimen rather than a perfect one has been se- 
lected for the photograph when possible. The upper figure of a plate 
is designated by “а,” and the lower by ‘‘b.’? Where no indication 
is given, it is to be understood that the material figured is at the Mis- 
souri Botenical Garden in St. Louis, or at the University of Illinois in 
Urbana,—the facilities of these institutions having been the main re- 
source of the author in the preparation of manuscript. 
FRONTISPIECE. DISTRIBUTION МАР, showing the principal regions 
indicated by the genus Phoradendron. 
North America: (1) Atlantic region, approximately that drained 
by the Mississippi river and the eastern streams, occupied by Phora- 
dendron only south of the Ohio and Missouri rivers; (2) Rocky Moun- 
tain region, oeeupied by Phoradendron only in its southern part which 
is seareely more than a northern Chihuahuan extension; (3) Califor- 
nian region, reaching Oregon; (4) Sonoran or desert region, essen- 
tially the valley of the lower Colorado river with the coasts and islands 
of the gulf of Baja California; (5) Chihuahuan region, connecting 
the Rocky Mountains with the eastern and western Sierra Madre 
ranges of Mexico; (6) Mexican table-land, lying between the Sierra 
Madre ranges and passing into the southern Chihuahuan region; (7) 
Sierra Madre ranges, confluent into (8) the Cordilleran or Guatemalan 
region, which itself passes into (9) the Isthmian or Costa Rican re- 
gion, reaching from Costa Rica into coastwise Venezuela; (10) Yuca- 
tecan region. 
South America: (11) Andean region, of great extent in the moun- 
tains, meeting the Isthmian region in Venezuela; (12) Bolivian re- 
gion, comprising the uplands of southwestern Bolivia and northwest- 
ern Argentina; (13) La Plata region,—no Phoradendron known from 
south of Uruguay; (14) Brazilian upland or southern Brazilian re- 
gion, limited in general by the valleys of the Amazon and Paraguay 
rivers; (15) Amazonian region; (16) Cayenne region, lying between 
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