April, 1905.] Key to Liverworts. 313 



thus modified and remaining at the bottom of the perianth rep- 

 resents the calyptra. It is soft and hyahne and in most cases 

 shorter than the perianth and not connate with it. 



It may be added that any suggestions in regard to the 

 improvement of this key wiU be thankfuhy received. 



Ah hverworts are usuaUy divided into two artificial groups, 

 the fohose and frondose, which are then subdivided as follows: 



Plant-body a leafy axis (Jungermanniaceae). 1 

 Plant-body a thallus. 30. 



1. Leaves incubous. 2. 

 Leaves succubons. 13. 



2. Leaves coniplicate-bilobed or with a small lower lobe. 3. 

 Leaves not complicate-bilobed or with a small lower lobe. 7. 



3. Lower lobe incurved-ventricose or saccate, seldom expanded. 4. 

 Lower lobe quadrate or roundish. (3. 



4. Lower lobe incurved, more or less ventricose. Lcjcimia. 

 Lower lobe saccate, seldom expanded. 5. 



5. Branches intra-axillary, the leaves on either side free. Fridlania. 

 Branches lateral, a basal leaf borne partly on the stem, partly on 



the branch. Jnbiila. 



6. Lower leaf-lobe c^uadrate. Raditla. 

 Lower leaf-lobe roundish. Porclla. 



7. Leaf-divisions numerous and capillary. 8. 

 Leaf-divisions not numerous and capillary. 9. 



8. Leaves bilobed, lobes subdivided and with ciliate margins. Perianth 



present, terminating short branches, sinooth, obovate, mouth 

 connivent, plicate-denticulate. Ptilidiuni. 

 Leaves 4-o-divided', divisions setaceously multifid and fringed. 

 Perianth none or rather forming together with the calyptra and 

 involucre a terminal or axillary, f.eshy and hairy torus. 



Trichocolca. 



9. Leaves deeply bilobed and 3-ranked (unclerleaves being similar- to 



leaves. Hcrbcrta. 

 Leaves not bilobed and 3-ranked. 10. 



10. Leaves entire (sometimes retuse) or 2-3-toothed. 11. 

 Leaves 2-4-cleft or parted. 12. 



11. Leaves entire (soinetimes retuse). Kantia. 

 Leaves 2-3-toothed. Bazzania. 



12. Leaves 3-(or seldom 4) parted; divisions capillary, formed by one 



row of cells. Blepharostoma. 

 Leaves palmately 2-4-cleft or -parted; divisions formed by more 

 than one row of cells. Lepidozia. 



13. Capsule opening irregularly into 4 irregular or dentate valves; plant- 



body pseudofoliaceous. Fossombronia. 

 Capsule opening regularly into 4 regular valves; plant body foli- 

 aceous. 14. 



14. Perianth absent; leaves closely imbricate and 2-ranked on short 



julaceous stems. Gymnomitriimi. 

 Perianth present. 15. 



15. Perianth connate to the middle or more with the involucral leaves. 16. 

 Perianth free or connate with calyptra. 17. 



Ifj. Perianth connate to near the summit; leaves complicate-bilobed. 



Marstipclla. 



Perianth connate to the middle; leaves entire or nearly so. Xardia. 



17. Perianth pendant, saccate; leaves bilobed, extending horizontally 



and at right angles from the stem; underleaves 2-cleft. Geocalyx. 



Perianth upright ; underleaves none or ovate-lanceolate or 2-4-cleft. 18. 



