ee ELS ee o is ea 
MELANTHACE FROM THE GENETIC STANDPOINT. — 139 
This very interesting monotypic genus differs from 7riantha and Tofieldia 
chiefly in the following points:— 
Triantha (Nutt.), Baker. Pleea, Michx. 
Bracts short. Bracts spathe-like. 
Flowers subtended by 3 connate Bractlets wanting. 
bractlets. 
Stamens 6. Stamens 9-12. 
Anthers rounded, erect. Anthers elongated, versatile. 
Pleea is evidently isolated, and a considerable amount of extinction must 
have occurred between it and its nearest relatives, Tofieldia, Triantha, and 
Narthecium. Regarding the comparison with Triantha, it is more likely 
that the bractlets subtending the flowers were suddenly lost by a negative 
mutation than that they were gradually reduced until they finally dis- 
appeared. The increase in size and change in shape of the bracts may 
have occurred independently, as also the addition of one or two whorls of 
stamens. The change from the short, subglobose, erect, terminal antlers of 
Tofieldia to the long, narrow, versatile anthers of Pleea probably involved 
several different germinal changes. Some species of Luzula have elongated 
erect anthers, so the versatile character probably appeared through an 
independent change in a related ancestral line. 
` 
4. NARTHECIUM, Moehring. 
. NARTHECIUM OSSIFRAGUM, Huds. Fl. Angl. 145 ; Sm. in Engl. Bot. viii. 
(1799) t. 535. 
N. anthericoides, Hoppe, in Mert. & Koch, Deutschl. F1. ii. (1826), 559. 
N. palustre, Bub. Fl. Pyren. iv. (1901) 169 *. 
Anthericum ossifragum, Linn, Sp. Pl. (1758) 446; Fl. Dan. (1761) t. 42. 
Abama ossifraga, DC. in Lam, Fl. Fr. ed. 2, iii. 171; DC. in Redouté, Lil. iv. (1808) 
t. 218. 
Europe. 
— 
. NARTHECIUM AMERICANUM, Ker, in Bot. Mag. (1812) t. 1505. 
N. ossifragum, var. americanum, A. Gray, Man. ed. 5 (1867) 536. : 
Abama americana, Morong, in Mem. Torr. Bot. Club, v. (1894) 109; Ann. Rep. NJ. 
State Mus. 1910 (1911) 338, pl. 33. ff. 2-3; Bartonia, iv. (1911) 1, t. 1. 
Pine barren swamps, southern New Jersey, and Delaware. ` 
This species is extremely local in its distribution. It was discovered by 
Pursh at Quaker Bridge, New Jersey, about 1805. He sent plants to Kew, 
from which the figure was made for the ‘Botanical Magazine. Witmer 
Stone t gives an account of its present distribution. After the lapse of a 
n2 
* A full list of figures is given here. 
+ Abama americana (Ker), Morong, in * Bartonia, iv. (1911) 1-5. 
