492 NECKERACEAE. 



than 3 cm. long, simple or branched, when young more slender and flagellate, 

 with smaller, less crowded leaves, when older with erect-appressed, crowded 

 plicate leaves, up to 1.5 mm. long by 0.33 mm. broad at base; vein usually 

 single, seldom double with a short accessory basal branch; alar cells fewer on 

 one side, up to 8-10 rows, seldom reaching the vein; margins entire, revolute 

 almost to the serrulate apex; cells spindle-shaped, with minute, terminal papil- 

 lae on both surfaces. Flowers and fruit unknown; propagating by small 

 septate brood-bodies borne in axillary clusters. 



On trees in coppices, New Providence and Andros : Florida ; Cuba ; Porto Rico ; 

 Costa Rica and Panama. FLORIDA LEUCODONTOPSIS. 



Family 9. NECKERACEAE Schimper. 

 NECKERA FAMILY. 



Plants usually growing on trees with creeping stems and pendent 

 branches, either simple or pinnately decompound, sometimes quite den- 

 droid; branches usually densely leafy, with crowded or imbricate leaves, 

 sometimes in 2-4 ranks. Leaves symmetric or inequilateral, various, cos- 

 tate or ecostate, entire or serrate, smooth or papillose; the perichaetial 

 usually quite different from the others, often surrounding: and covering the 

 capsule. Usually dioicous. Pedicel often short and straight, immersed, 

 rarely curved or exserted; capsule ovoid or cylindric; smooth or ribbed; 

 lid conic, beaked; calyptra smooth or hairy; peristome usually double, the 

 inner more or less rudimentary; annulus present or absent. A large 

 family, of 50 genera and several hundred species, of wide temperate and 

 subtropical distribution. 



1. PIREELLA 'Cardot, Eev. Bryol. 40: 17. 1913. 



[PiREA Cardot, Bull. Soc. Bot. Belg. 32: 175. 1893. Not Durand, 1888.] 



Stems creeping, slender and radiculose ; branches erect, 2-4 cm. long, simple 

 or pinnately branched, blunt, or rarely slender and flagellate; leaves crowded, 

 appressed, erect or spreading; stem -leaves ovate, abruptly acuminate, entire, 

 ecostate; branch-leaves lanceolate, acuminate, entire or serrate at apex; vein 

 thin, wider at base, ending below the apex; cells more or less thickened and 

 porose, linear at base ; alar cells quadrate, shorter and broader with thick walls. 

 Perichaetial leaves, erect, ovate or lanceolate-acuminate, or subulate. Dioicous, 

 often sterile and propagating by brood-bodies. Pedicel exserted, erect, some- 

 what rough above, seldom short or immersed; capsule mostly exserted, calyptra 

 cucullate, hairy; lid small, beaked; mouth small; peristome double, its teeth 

 lanceolate, more or less bifid, smooth, pale or red; endostome hyaline, mem- 

 branous, adherent to the teeth; spores smooth. [Diminutive of Pirea.~] A small 

 genus of 10 species, confined to tropical and subtropical regions of North and 

 South America. Type species: Pireella cavifolia Cardot & Herzog. 



1. Pireella cymbifdlia (Sull.) Cardot, Eev. Bryol. 40: 17. 1913. 



Pilotrichum cymbifolium Sull. in A. Gray, Man. ed. 2, 681. 1856. 



Plants usually growing on trees. Stems slender, creeping and rooting, the 

 terminal growths slender with small acuminate leaves only about 0.5 mm. long, 

 with a short vein and faintly serrate margins, the alar cells few and rectangu- 



