JUNGERMANNIACE^E. (SCALE-MOSSES.) 703 



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. 



-i- 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 



mtra-axillary, the leaves on either side free. 



2. .1 uh iila. 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. 



5. Porella. Lower lobe ligulate. Perianth triangular, the third or odd angle ventral. 



+ ** Root-hairs rising from the lower lobes. 



^^ 



4. Badula. Perianth compressed. Underleaves none. 



i- -i- Upper lobe smaller than the lower, or the two somewhat equal. 

 ** Leaves succubous as to their lower lobes. 



15. Scapaiiia. Involucral leaves 2 ; perianth dorsally compressed, the mouth truncate, 



bilabiate, decurved. 



16. Diplophyllum. Involucral leaves few; perianth erect, round, the mouth denticulate. 



H- -H- Leaves transverse. 



25. Marsupella. Perianth tubular or somewhat compressed. (Compare also Junger- 

 mannia Sphenolobus. ) 



* * Leaves palmately 3-4- (or many-) cleft. 

 <- Divisions numerous, capillary. Plants large, usually in conspicuous mats. 



6. Ptilulinm. Leaves palmatifid with ciliate margins. 



7. Trichocolea. Leaves setaceously multifid. 



t- -i- Leaves 3 - 4-cleft or parted ; plants small, mostly inconspicuous. 



10. L,epiclozia. Leaf-divisions two cells wide or more. 



11. Blepharostoma. Leaf-divisions only one cell wide. 



* * * Leaves entire, emarginate, or 2 - 3-toothed or -lobed. 



<- Leaves closely imbricate on short julaceous stems. 

 27. Gymnomitriurn. Involucre double, the inner shorter. 



i- -)- Leaves deeply bilobed. 



8. Herberta. Underleaves large. Perianth fusiform on an elongated branch. 



1-. Cephalozia. Underleaves mostly wanting; perianth mostly triangular on a short 



branch. 



-i K -)- Leaves incubous, mostly plane or depressed. 



9. I>azzania. Leaves mostly 2 -3-toothed. Perianth fusiform on a short branch. 

 14. Kautia. Leaves mostly entire. Perianth fleshy, pendulous, subterranean. 



+- -i- >- >- Leaves succubous or transverse. 

 H- Underleaves entire or nearly so. 



13. Odontosehisma. Involucral leaves numerous, small, incised, those of the stem 

 rounded or retuse. 



21. Mylia. Involucrai leaves 2, connate at base. Large. 



22. Harpanthns. Involucral leaves few, smaller than the semi-vertical emarginate stem- 



leaves. Small. 



