Pl.celLaph. 2. THALASSIOPHYTiE. 63. Gastrid. 319 
Sea-shores; annual; summer. 
Thallus 6 to 12 inches long, twice or thrice pinnate. 
jS. hylridum. Thallus almost cylindrical, rather cartila- 
ginous; twigs slightly attenuated at the bottom, and rounded 
at the tip. 
b. Gastridium. Thallus even , or unequally contracted into 
apparent joints ; tubercles on the sides . 
3. Gastridium ovale. Oval belly-weed. 
Thallus nearly cylindrical, threadlike, irregularly two- 
forked, below naked, covered above on all sides with simple 
elliptical twigs. 
Fucus ovalis, Huds. Fl.Angl. 573; Engl. Bot. 711 ; Turn. Hist. 81. 
Fucus sedoides, Stackh. Ner. Brit. 07. 
Fucus vermicularis, Lightf. Scot. 958. 
Gigartina ovalis, Lumour. That. 
Chondria ovalis, Agardh Disp. 18. 
Submarine rocks; annual; summer. 
Thallus 3 or 4 > inches high ; pale reddish brown. 
#. bolryoides. Twigs short, nearly globular. 
Fucus botryoides, Wulf. in Jacq. Collect. 3, 146. 
y. subarticulatum. Twigs long, linear, contracted as if 
jointed. 
4>. Gastridium tenuissimum. Very thin belly-weed. 
Thallus gelatinous, threadlike, cylindrical, pinnately 
branched; branches alternate, spreading, mostly simple; 
twigs cylindrical, simple, scattered. 
Fucus tenuissimus, Gooden, in Tr. Lin. Soc. 3,215; Engl. Bot. 1682 ; 
Turn. Hist. 100. 
Ulva capillaris, Huds. 571. 
Gigartina tenuissima, Agardh Disp. 18. 
Sea-shore, or on other marine plants; annual; summer. 
Thallus pale flesh-colour, tender, 6 to 10 inches long. 
5. Gastridium purpurascens. Purplish belly-weed. 
Thallus threadlike, branched ; branches and twigs two- 
rowed, nearly opposite; last ones pinnate; segments small, 
opposite. 
Ulva purpurascens, Huds. Ft. Angl. 569. 
Gastridium purpurascens, Lyngbye Hydr.Dan. 69. 
Sea-shore ; annual ; summer. 
Thallus 6 to 9 inches high, attenuated at bottom, tubu- 
lar, apex acute; branches smaller at each end, spreading; 
segments lanceolate. 
