Addisonia 1 1 



(Plate 126) 



OKENIA HYPOGAEA 

 Dune-groundnut 



Native oj Florida and southern Mexico 

 Family Aluoniaceae Four-o'ci.ock Family 



Okenia hypogaea Schlecht. & Cham. Linnaea 5: 92. 1830. 



Plants with a stout tap-root from which few or many stems arise. 

 The stems and branches are prostrate, two to seven feet long, radi- 

 ally disposed and thus forming a broad mat. They are tomentose 

 with short and long viscid-glandular hairs, very clammy. The 

 leaves are opposite, sometimes clustered at the nodes, fleshy, very 

 unequal in size. The blades are ovate, a half inch to two and a half 

 inches long, obtuse at the apex, undulate-sinuate, broadly cuneate 

 to cordate at the base, bright green on the upper side, somewhat 

 paler beneath, pubescent with short and long viscid hairs on both 

 sides, but more closely pubescent beneath, closely ciliolate, rather 

 conspicuously ribbed, often prominently so beneath. The petioles 

 are nearly as long as the leaf-blades or shorter, pubescent like the 

 stem and branches. The short-pedicelled flowers are erect, arising 

 from a short-stalked involucre, which resembles a calyx, of three 

 ovate or ovate-lanceolate pubescent bracts. The calyx is very 

 showy, trumpet-shaped; the tube is green or nearly white, viscid- 

 pubescent without; the throat is white or green, glabrous; the limb 

 is bright rose-purple or sometimes deep-blue, an inch to an inch 

 and a quarter in diameter, or much smaller in the later flowers, with 

 the five spreading lobes notched. The stamens are fifteen or fewer, 

 with the capillary filaments white or nearly so at the base, magenta 

 above. The anthers are pale yellow, two-lobed. The ovary is 

 ovoid, terminated with a capillary style which is surmounted with 

 a depressed stigma. The fruits are subterranean, produced from 

 the flowers that have buried themselves by the elongated pedicels 

 which are pubescent near the base and glabrous near the flower and 

 fruit; they are ellipsoid and about five-eighths of an inch long, with 

 a pale or white ten-ribbed pericarp. 



One of the numerous surprises in the course of our botanical ex- 

 ploration of southern Florida was the discovery of this plant, not 

 previously known in the coastal region north of southern Mexico. 

 It was found by J. J. Carter and the writer on the sand-dunes 

 opposite Miami, in November, 1903. Curiously enough, it repre- 

 sents the species on which the genus Okenia was founded. The 

 original specimens were collected on sand-hills near Veracruz, about 

 the end of the first quarter of the last century by Christian 

 Schiede and Ferdinand Deppe. The plant was little known up to 



