Herbs or more rarely low shrubs; leaves simple, entire, sessile, alternate, opposite or subverticillate below; flowers cymose, hermaphrodite, regular, symmetrical, hypogynous, the calyx strongly imbricated, petals convolute in the bud; fruit a many-seeded pod, having twice as many cells as there are styles, seeds oily.
I. Linum. (Tourn.) L.
1. L. Lewisii. Pursh. Wild Flax.
Plants with astringent roots; leaves toothed, lobed or divided, stipulate; flowers hypogynous, perfect, regular, numerous, sepals imbricated in the bud, persistent; fruit ovary deeply lobed, carpels two-ovuled, one-seeded, separating elastically with their long styles when mature from the elongated axis.
I. Geranium. (Tourn.) L.
1. G. Richardsonii. F. and M. White Geranium.
2. G. carolinianum. L. Carolina Crane's Bill.
3. G. Bicknellii. Britton. Bicknell's Geranium.
Chiefly aquatic herbs, low, slender, usually tufted; leaves entire, spatulate or linear; flowers monoecious, solitary or a few together in the axil of the leaf, wholly naked or enclosed by a pair of membranaceous bracts; fruit nut-like, compressed, seeds pendulous.
I. Callitriche. L.
I. C. palustris. L. Water Fennel.