ADDISONIA 33 
(Plate 17) 
EXOGONIUM MICRODACTYLUM 
Slender Red Exogonium 
Native of Florida and the northern West Indies 
Family CONVOLVULACEAE MOorRNING-GLORY Family 
Ipomoea microdactyla Griseb. Cat. Pl. Cub. 204. 1866. 
Ipomoea fuchsioides glabra Griseb. Cat. Pl. Cub. 205. 1866. (According to 
House.) 
Exogonium microdactylum House, Bull. Torrey Club 35: 102. 1908. 
Exogonium microdactylum integrifolium House, Bull. Torrey Club 35: 103. 1908. 
A glabrous, slightly succulent, trailing or climbing vine, some- 
times spinulose, with flattened triangular short spines near the base, 
sparingly br renckiag, and attaining a length of ten feet or more, 
arising from a thick, tuber-like root which is rtp six inches 
long. The vslender-petiled eine leaves are ous in form 
and outline, ovate to lanceolate or oblong, and ihe sitting or 
palmately lobed or almost divided, or with a pair of short basal 
lobes; the blades are longer than the petioles, sometimes four inches 
dong usually shorter. The pedicelled flowers are in small clusters 
r solitary at the leaf-axils; these clusters are often numerous and 
Riooh together along the upper part of the plant. The green calyx 
is about a quarter of an inch long, composed of five round-ovate, 
obtuse sepals. The scarlet, deep red, or carmine salverform corolla 
has a slender tube one inch to one and a half inches long, somewhat 
thicker above than below, and a widely spreading limb about one 
inch across, with five broadly ovate, pointed lobes. The five stamens 
and the stigmas project somewhat beyond the corolla-tube. The 
ovary is sae The fruit is a nearly globular, pointed Sites 
about half an inch thick, containing about four flat seeds about one- 
quarter of an inch long, each of which bears a tuft of cotton-like, 
brownish hairs. 
This vine inhabits poor soil, rocky, gravelly, or sandy, in southern 
Florida, nearly throughout the Bahama Islands, and in all provinces 
of Cuba, extending to the Isle of Pines. A similar, perhaps iden- 
tical, species occurs on the limestone plateau of Mona Island, in 
the Mona Passage, between Santo Domingo and Porto Rico, but 
the specimen collected there is not complete enough for certain 
identification (Ann. Missouri Bot. Gard. 2:47). OnInagua Island, 
Bahamas, it is called ‘‘ wild potato.”’ In Florida its distribution is 
wholly or mainly in pinelands, as also on the Isle of Pines, but in 
the Bahamas and Cuba it grows over large areas in which pine trees 
do not exist. 
