DISTRIBUTION OF LIVERWORTS. 285 



Considering the proximity of our Southern region to the tropics, 

 where these plants attain such a high development, the small number 

 of forms which are held in common with tropical America, ano^ which, 

 on this continent, are not found outside of warmer temperate regions, 

 such as Dumortiera, Eeboulia, and Sphaerocarpus, is remarkable. 

 Most of the genera represented in greatest numbers in the cooler tem- 

 perate region (Alleghenian area), and more or less of a cosmopolitan 

 distribution, are met with in every part of the State for example, Eic- 

 cia, Kicciella, Marchantia, Eiccardia, Cephalozia, Plagiochila, Porella, 

 Scapania, Lejeunea, Frullania, and others. There can be little doubt 

 that some of the genera prevailing in the Northern States and Canada, 

 not yet known from Alabama, will be added to our flora by a closer 

 search for the plants in the Mountain region. 



About one-half of the species known from Alabama belong strictly 

 to Eastern North America ; 14 species are held in common with 

 Europe, and 11 occur on the Pacific slope, mostly in its northern exten- 

 sion, all of which, with the exception of Asterella tenella, are also widely 

 distributed in the cooler temperate zone of Europe. 



Little more than one-half of the liverworts so far reported from the 

 State are of a decided Southern distribution. Strictly confined to the 

 subtropical district (Louisiauian life area) are the following : 



Marchantia disjuncta. Lejeunea mohrii. 



Sphaerocarpus terrestris. Lejeunea auriculata. 



Fossombronia faveolata. Frullania kiinzei. 



Plagiochila liidoviciana. Frullania caroliniana. 



Cephalozia media ( ?). Frullania donnellii. 



Phragmidium xanthocarpa. Anthoceros carolinianus. 



Lejeunea austini. Anthoceros ravenelii. 



The following are confined within the warmer temperate zone (Caro- 

 linian life area) : 



Eiccia lamellosa. Cephalozia virginica. 



Eeboulia hemispherica. Bazzania trilobata. 



Dumortiera hirsuta. Phragmicoma clypeata. 



Pallavicinia lyellii. Lejeunea serpyllifolia. 



Fossornbronia angulosa. Frullania squarrosa. 

 Plagiochila undata. 



The species extending to the cooler temperate and frigid regions are 

 scattered over the State from the Gulf shore to its northern limit. 



The specimens early collected by the writer were identified by the 

 late Mr. C. F. Austin. His collections of later years have been exam- 

 ined by Professor Underwood, to whom thanks are due for this, as also 

 for his assistance in revising the list of Hepaticae from Alabama. 



