ADDISONIA 31 
(Plate 176) 
JEFFERSONIA DIPHYLLA 
Twin-leaf 
Native of eastern United States 
Family PoDOPHYLLACEAE May-appLeé Family 
Podophyllum diphyllum U,. Sp. Pl. 505. 1753. 
Jeffersonia binata Barton, Trans. Am. Phil, Soc. 3: 342. 1793. 
Jeffersonia diphylla Pers, Syn. Pl. 1: 418. 1805. 
Among the wild flowers of eastern North America there are two 
of strikingly similar habit, yet always classified as members of 
different families. These are the bloodroot (Sanguinaria) and the 
twin-leaf. They agree in having short, thick rootstocks, from 
which arise in early spring simple scapes, each with several sheathing 
scales and one or more basal leaves, and each bearing a single ter- 
minal flower about an inch in diameter. In both the sepals are 
fewer than the petals, and drop off as the flower expands, while the 
petals are white and are eight or more in number; the leaves are 
~ small at flowering-time, becoming several times as large later in the 
season. ‘These remarkable points of resemblance may well make 
us wonder whether our ‘‘natural’” system of classification is, in 
the present instance, so natural after all. 
innaeus, in his historic work entitled “Species plantarum” 
(1753), attempted to enumerate all of the known kinds of plants, 
and assigned to each a double name, the first standing for the 
genus and the second for the species, a method never before con- 
sistently applied, but in almost universal use since that time. 
For the most part he merely gave new names to plants previously 
known; among the very few described as new, however, was the 
twin-leaf. He knew it only from fruiting specimens collected in 
Virginia by John Clayton, and was very doubtful of its relationship; 
he referred it, however, to the same genus with the may-apple 
(Podophyllum peliatum) calling it Podophyllum diphyllum. His 
botanical acumen is shown by the fact that all modern works recog- 
nize the close relationship of the two plants. 
When Barton, with a far better knowledge of the twin-leaf, 
distinguished it as the type of a new genus, he named it Jeffersonta, 
in honor of Thomas Jefferson. This was seven years before the 
commencement of Jefferson’s first term as president, while he was 
secretary of state in Washington’s cabinet. Jefferson was noted 
