A REVISION OF SYNGONIUM (ARACEAE)
THOMAS B. CROAT"' #
Thirtythree species are recognized for Syngonium
in this first published revision since that of Engler and Krause
in 1920. Syngonium (now including Porphyrospatha)
is the only member of the tribe Syngonieae (Araceae).
The genus includes 4 newly described sections, sect. Oblongatum
Croat, sect. Cordatum
Croat, sect. Pinnatilobum
Croat, and sect. Syngonium
Croat, defined by leaf morphology, namely by blades basically oblong,
cordate, pinnately lobed, and pedately lobed, respectively.
Eleven new species are described: S.
chocoanum (Colombia: Choco),
S. dodsonianum (Ecuador: Los Rios), S.
foreroanum (Colombia: Choco), S.
gentryanum (Peru: Hudnuco), S.
glaucopetiolatum (Costa Rica, Panama), S.
harlingianum (Ecuador: Pastaza), S.
laterinervium (SW Costa Rica, NW Panama), S.
llanoense (Panama), S.
sparreorum (Ecuador: Cotopaxi),
S. steyermarkii (Guatemala and SE Mexico), S.
triphyllum (Honduras to Panama).
The genus Syngonium, interpreted here
to include the genus Porphyrospatha, is one of two genera
of Araceae (the other being Monstera) with a center
of diversity in Central America. The following revision of Syngonium
includes 33 species of which 11 species are described as new to
science. Three species are transferred to Syngonium from
other genera, namely Philodendron (2 spp.) and Porphyrospatha
Although the genus needs more field work, especially
in South America, the present revision is the culmination of field
work conducted in Central America and northern South America over
the past decade.
1 P. A. Schulze Curator of Botany, Missouri
Botanical Garden, Post Office Box 299, St. Louis, Missouri 63166.
2 This study was sponsored in part by NSF Grant
DEB77-14414AOI. ANN. MISSOURI BOT. GARD. 68: 565-651. 1981.