Tribe IV
ULVACEÆ.
Frond membranous, continuous, tubular or flattened, never ribbed, herbaceous, or very rarely purple. Fruit a heap of sporules, either naked , or forming scattered granules covered by coniocystas. 2304. Vaucheria. Filaments dichotomous or irregularly branched, somewhat rigid. Fructification; a granulated mass within the frond, and external dark vesicles variously sinuated. 2305. Codium. Frond spongy, of a determinate figure formed of filaments densely packed, which are tubular and continuous, and colored by a granular green powder. Coniocystas clustered at the surface of the frond. continuous, and colored by a granular green powder. Coniocystas clustered at the surface of the frond. 2306. Bryopsis. Root minutely scutate. Filaments tubular, continuous, aggregated, branched, pinnate, or imbricated upwards with branchlets. Fructification a dark internal granular mass. 2307. Solenia. Frond tubular, membranous, with a striated areolated surface. Sporidia very minute and compact. 2308. Ulva. Root scutate. Frond plane, ribless, flabelliform or wedge-shaped, or linear and dichotomous. Fructification naked immersed; granules distributed in fours throughout the frond. 2309. Porphyra. Frond flat, purple, with the membrane of equal texture. Fruit twofold; first, sori of oval sporidia collected in a disorderly manner; second, two parallel lines marked on each side by a globule. sporidia collected in a disorderly manner; second, two parallel lines marked on each side by a globule.