PL cell. aph. 1. HYDROPHYTE. 16. Conjug. 299 
Ponds; August. 
Tufts thick, dark green, floating; threads as thick as a 
horse-hair ; transverse tubes very short. 
XVII. 17. CHOASPIS. Choaspis. 
Thallus threadlike, simple, tubular, jointed, kneebent; 
coupling at the bend, by a perforation in each joint, which 
transmits the granules from one plant to the other, where 
they form an elliptic spore; granules scattered. — Not 
slippery. 
Choaspis serpentina. Serpentine choaspis. 
Threads slender, stiff, here and there slightly bent, and 
coupling; joints four times as long as broad; granules in a 
triple irregular series. 
Conferva stictica, Engl. Bot, 2463. 
Ditches. 
Tufts floating, pale yellowish green above, blackish 
green beneath ; joints when young pale green. 
XVIII. 18. AGARDHIA. Agardh. 
Thallus threadlike, simple, tubular, jointed, bent, ap- 
proximating and uniting here and there with others, the 
coupled joints becoming shortened; granules in a single 
line, spore formed in the shortened coupled joints, cross- 
shape. — Bluish green. 
Agardhia ccerulescens. Bluish agardh. 
Threads slender, bent, light purplish blue; joints 6 times 
as long as broad ; granules and spores greenish. 
Conferva caerulescens, Engl. Bot. 2457. 
Conferva conjugata, Agardh Syn. 96. 
Conferva Agardhiana, Wallin, in Liljebl. Sv. FI. cd. 3. 
Zygnema? caerulescens, Agardh bisp.ed. 2,32. 
Boggy pools ; July. 
Joints pellucid with a central, slightly spiral, dotted line 
of green granules. 
XIX. 19. SERPENTINARIA. Serpentinare. 
Thallus threadlike, simple, tubular, jointed, knee-bent, 
coupling at the bend, by a short transverse tube coming 
from the middle of the joints, which receives the granules 
from each plant, and thus forms a globular spore remain- 
ing in the middle of the transverse tube ; granules scattered. 
— Slippery. 
