JUNGERMANNIACEAE. 509 



6. MICROLEJEUNEA [Spruce] Jack & Steph. Bot. Centrb. 

 60: 107. 1894. 



A somewhat artificial genus differing from Lejeunea in its smaller size and 

 relatively larger lobules, the latter often equaling the dorsal lobes in length. 

 Structure of the lobes, lobules, underleaves and floral organs very similar in 

 the two genera. [Greek, minute Lejeunea.] About 70 species, mostly tropical. 



Lobule about half as long as the dorsal lobe ; leaf-cells averag- 

 ing about 20 /A. 1. M . laetevirens. 



Lobule nearly as long as the dorsal lobe; leaf-cells averaging 



about 12 /*. 2. M. bullata. 



1. Microlejeunea laetevirens (Nees & Mont.) Evans, Bryol. 11: 68. 1908. 



Lejeunea laetevirens Nees & Mont, in Sagra, Hist. Cub. 9 : 281. 1845. 



Plants pale green, scattered or growing in depressed mats. Leaves distant 

 to snbimbricated, the dorsal lobe obliquely spreading, ovate, about 0.25 mm. 

 long, rounded to obtuse at the apex; lobule inflated, about half as long as the 

 lobe, ovate, involute, apex tipped with a single, almost straight, blunt cell; 

 leaf cells averaging about 20/i in the middle of the lobe, thin-walled through- 

 out or with minute trigoues; underleaves distant, ovate, bifid about one half 

 with acute or acuminate divisions and a narrow sinus, often unidentate on one 

 or both sides; inflorescence dioecious; female inflorescence borne on a short 

 branch, with one or two subfloral innovations; bracts a little larger than the 

 leaves, the lobule rounded to acuminate; bracteole free, ovate; perianth pyri- 

 form, the keels smooth. 



On bark, Abaco, Berry Islands, Andros, New Providence, and Cat Island : Vir- 

 ginia ; Florida to Louisiana ; widely distributed in tropical America. YELLOWISH 

 GREEN MICROLEJEUNEA. 



2. Microlejeunea bullata (Tayl.) Evans, Mem. Torr. Club 8: 164. 1902. 



Lejeunea lullata Tayl. Lond. Journ. Bot. 5: 398. 1846. 



Plants pale or bright green, scattered or forming loose depressed mats. 

 Leaves distant, the dorsal lobe erect or slightly spreading, ovate, about 0.15 

 long, rounded at the apex, entire or nearly so; lobule strongly inflated, almost 

 as long as the lobe, ovate, usually involute, the apex tipped with a single, 

 almost straight, blunt cell; leaf cells averaging about 12/4, usually thin-walled 

 throughout; underleaves distant, ovate to orbicular, bifid more than one half 

 with suberect, subulate lobes and a broad sinus, margin entire; inflorescence 

 dioecious; female inflorescence borne on an elongated branch with a single sub- 

 floral innovation; bracts about twice as long as the leaves, the lobe rounded to 

 acute, the lobule narrower, usually acute; bractole slightly connate, oblong, 

 bifid less than one half with sharp divisions; perianth pyriform, the keels 

 smooth. 



On bark, New Providence and Crooked Island : southern United States ; trop- 

 ical America. INFLATED MICROLEJEUNEA. 



7. RECTOLEJEUNEA Evans, Bull. Torr. Club 33: 8. 1906. 



Differs primarily from Lejeunea in its flattened perianth with sharp lat- 

 eral keels. Dorsal lobes, lobules and underleaves similar, but the lobes com- 

 monly broader; ocelli sometimes present among the leaf -cells; vegetative repro- 

 duction by means of specialized caducous leaves. [Greek, fragile Lejeunea.] 

 About 40 species, largely of tropical America. . Type species: E. flagelliformis 

 Evans. 



