3*8 47. Palmel. 2.THALASSI0PHYTiE. Pl.cell.aph . 
XXII. 47. PALMELLA. Lyngbve. Trembler . 
Thallus cylindrical^ simple or branched, solid; integu- 
ment membranaceous; inside gelatinous, cellular ; sporidia 
globular, immersed in the thallus. — Marine. 
1. Palmella defracta. Broken trembler. 
Thallus threadlike, simple, twisted, elastic, viscid, pel- 
lucid ; sporidia globular, pale red. 
Ulva defracta, With. Bot. Arr. 4, 124; Engl. Bot. 1-626. 
On sea-plants. 
Thallus 2 to 12 inches long, l-8th inch in diameter. 
2. Palmella elminthoides. Wormlike trembler . 
Thallus threadlike, mostly simple, opake, slippery, rather 
blunt; central line dark, parenchymatous; sporidia very 
minute, opake. 
Ulva elminthoides, With. Bot. Arr. 4, 141. 
Rocks in the sea; July. 
Thalli aggregated, 4 to 7 inches long, twisted. 
XXIII. 48. MERRETTIA. Merrett . 
Thallus flat, diversely shaped, solid ; integuments mem- 
branaceous; inside cellular, gelatinous; sporidia scattered, 
immersed. 
1. Merreltia adnata. Adnate merrett. 
Thallus diversely shaped, gelatinous, wrinkled, brownish 
yellow; sporidia globular, brown. 
Tremeila adnata, Hudson FI. Angl. 565. 
Palmella adnata, Lyngbye Hydr. Dun. 205. 
On rocks between high and low water in the sea. 
Thallus wrinkled, 3 to 6 inches in diameter, less than a 
quarter thick. 
2. Merrettia coriacea. Leathery merrett. 
Thallus flat, adnate, very wide, indeterminate, smooth, 
slippery, dull red; sporidia globular, 
Ulva rupestris, Engl. Bot. 2194. 
Upright faces of fells over which water trickles. 
Thallus 2 or 3 feet wide, resembles a spread-out piece of 
very wet reddish or greenish brown washed leather, but is 
not so tenacious; has been mistaken for flesh. 
