Order 137. JUNGERMANNIÀCEÆ. Scale-Mosses.
Plant-body a leafy axis or rarely thallose. Capsule borne on a slender often elongated pedicel, splitting at maturity into 4 valves. Elaters mixed with the spores, mostly bispiral (unispiral in n. 1–3, 32, and 33, 1–3-spiral in n. 5 and 28). Antheridia and archegonia diœcious or monœcious, in the latter case either mingled in the same inflorescence, or separated upon the same branch, with the antheridia naked in the axils of the lower leaves, or on separate parts of the same plant. Leaves 2-ranked, incubous (i.e. the apex of each leaf lying on the base of the next above), or succubous (i.e. the apex of each leaf lying under the base of the next above), or sometimes transverse, with frequently a third row of rudimentary leaves beneath the stem.
Artificial Key to the Genera.
§ 1. Plant-body a leafy axis.
[*] Leaves complicate-bilobed (i.e. folded together) or with a small basal lobe.
[+] Lower lobe smaller than the upper.
[++] Root-hairs borne on the stems or underleaves.
1. Frullania. Lower lobe mostly saccate, more or less remote from the stem. Branches intra-axillary, the leaves on either side free.
2. Jubula. Lower lobe saccate; branches lateral, a basal leaf borne partly on the stem, partly on the branch.
3. Lejeunea. Lower lobe incurved, more or less inflated.