The Manual of the Botany of the Northern United States / Including the District East of the Mississippi and North of North Carolina and Tennessee

by Asa Gray

24. Jungermannia. Involucral leaves few, mostly larger than the entire or bidentate stem-leaves. Medium-sized or large.

[++][++] Underleaves 2–4-cleft, -parted, or -divided.

17. Geocalyx. Involucre fleshy, saccate, pendent. Leaves bidentate; underleaves 2-cleft.

18. Lophocolea. Fruit terminal on the main stem or a primary branch. Involucral leaves distinct.

19. Chiloscyphus. Fruit on a short lateral branch. Involucral leaves distinct. (See also Jungermannia.)

[++][++][++] Underleaves mostly wanting.

a. Leaves entire or barely retuse.

23. Liochlæna. Involucral leaves distinct, like those of the stem; perianth truncate-depressed at the apex.

26. Nardia. Involucral leaves connate at base and adnate to the perianth.

b. Leaves bidentate or bilobed, rarely 3-lobed.