Neptunia
(so called after Neptune, god of the sea; in reference to the species growing in lakes and ponds). ORD. Leguminosae. A genus comprising about eight species of diffuse, prostrate, or floating perennial herbs or sub-shrubs, inhabiting North and South America, tropical Asia, and Australia. Flowers in globular heads, the lower ones barren, with elongated petals; the upper ones fertile, with definite stamens, as in Desmanthus. Leaves bipinnate; leaflets small. N. plena, the only species yet introduced, thrives well in a stove aquarium, or in tubs or pans filled with water, having a few inches of soil in the bottom. The white, spongy, lower portion of the stems, full of air-cells, enabling the plant to float, are very remarkable. The leaflets and petioles are as irritable as those of Mimosa pudica, and are of an extremely delicate yellow-green colour.
N. plena (abounding). fl. pale yellow; peduncles bracteate. July to September. l. with two to four pairs of pinnae, and each pinna bearing twelve pairs of leaflets. Stems prostrate, compressed. Tropics, 1733. Sub-shrub. (B. M. 4695.)