DicranocJmete reniformis Hieronymus 1887, p. 293; 1892, p. 370 



PL 19, Figs. 1, 2 



Cells small, epiphytic, hemispherical in side view (reniform in 

 vertical view), with a branched, vertical gelatinous bristle arising 

 from the base of the cell. Chloroplast bell-shaped and nearly cover- 

 ing the cell wall. Cells 7-12-(32)/x in diameter; setae 40-80- ( 160 );Lt 

 long. 



Rare on algae in shallow water. Mich., Wis. 



FAMILY TRENTEPOHLIACEAE 



In this family, branched filaments form cushion-like or felt-like 

 thalli in which there are horizontal portions giving rise to vertical 

 branches. Most genera are without setae or hairs. Another different- 

 iating character is the presence of swollen, somewhat specialized 

 cells for zoospore or gamete production. These are usually borne 

 at the ends of vertical branches. The family as a whole takes up 

 rather unique habitats. Some perforate wood and shells or form 

 encrusting growths over rocks in aerial situations. Trentepohlia 

 forms yellow- or brick-red, felt-like encrustations on trees and 

 stones, especially in humid climates. Other forms are endo- or 

 epiphytic on higher plants — Cephaleuros, for example, which is 

 capable of producing pathological conditions in the leaves of several 

 southern and tropical angiospenns. Two genera only, Gongrosira 

 on shells and Trentepohlia on moist, aerial substrates, are represent- 

 ed in our collections. 



GONGROSIRA Kuetzing 1843, p. 281 

 An attached, branched thallus with pseudoparenchymatous, pros- 

 trate, and entangled branches giving rise to short, erect filaments 

 terminating in enlarged cells. Crowing on wood and old shells; 

 sometimes with rhizoidal branches penetrating the substrate. Cells 

 cylindrical or claviform, with thick, sometimes lamellated walls. 

 Chloroplast 1, a parietal plate with 1 to several pyrenoids. 



Key to the Species 



Thallus flat; cells slender, 6-14^ in diameter, forming both 



horizontal and downward-growing filaments G. lacustris 



Thallus pseudoparenchymatous, stouter; cells 15-30,a in diameter, 



forming horizontal, but not downward-growing, filaments G. Debaryana 



Gongrosira Debaryana Rabenhorst 1863, p. 223 

 PI. 19, Fig. 3 

 Attached to and forming green patches on wood, or on shells of 

 mollusks; possessing reduced horizontal branches, giving rise to 



[132] 



