CODIACEAE. 501 



dichotomous. In its typical condition, C. verticillata is a plant of lagoons 

 and of the mangrove association, being often found attached to the roots of 

 Bhisophora near the low-water mark. Its erect branches may then attain a 

 height of 1-6 inches and the dichotomous ramuli occur in a more or less 

 clearly defined succession of whorls or tufts. 



Family CODIACEAE. 



Avrainvillea nigricans Decaisne, occurs on rocks just below the low- 

 water mark, as at Gibbet Island and Harris Bay. It is spongy and blackish 

 and the flabelliform, cuneiform, or oblong upright part is in the Bermuda 

 specimens mostly only 2 or 3 inches high. Under the compound microscope 

 the filaments of the flabellum are found to be moniliform. (Phyc. Bor.-Am. 

 ^171.) 



Avrainvillea longicaulis (Kiitz.) Murr. & Boodle, occurs in the ponds of 

 Walsingham, where it gets to be more than a foot tall. It here has a long 

 stalk, finally terminated by an irregular flabellum that is sometimes several 

 inches long or broad. In external form, however, this species and A. nigri<:ans 

 often resemble each other closely and the best distinguishing characters are 

 found in the form of the filaments of the flabellum, which in A. longicaulis 

 are commonly cylindrie with a strong constriction at the base of each branch. 

 From the Udoteas, the Avrainvilleas are distinguished by their lack of calci- 

 fication, by their softer more spongy texture, and by their blackish or dusky 

 brown color. (Phyc. Bor.-Am. 2170.) 



Udotea Flabellum (Ell. & Soland.) M. A. Howe, is a more or less fan- 

 shaped calcified light yellowish green or dark olive-green plant, mostly 2-10 

 inches high, and showing concentric zonations. The flabellum has a compact 

 firm cortex. Forms occur in which the .flabellum is variously lobed and 

 laciniate. The species is rather common in 1-50 feet of water, growing 

 mostly on a sandy or muddy bottom. (Phyc. Bor.-Am. 1914.) 



TJdotea conglutinata (Ell. & Soland.) Lamour. is usually a smaller 

 lighter green plant, the flabellum of which is destitute of a highly specialized 

 cortex. Under a hand lens the surface of the flabellum appears spongiose or 

 longitudinally strigose. With a higher magnification each of the flabellum 

 filaments is seen to be enclosed in a porose calcareous sheath. This species 

 has been found on South Beach in Paget by Farlow and at Harris Bay by 

 Hervey. (Phyc. Bor.-Am. 1913.) 



PeniciUus capitatus Lamarck, the Merman's Shaving Brush, is common, 

 usually on a sandy or muddy bottom in shallow water. ^ It has a subterete and 

 strongly calcified stalk and a commonly subglobose head, the free dichotomous 

 filaments of which are each enclosed in a porose calcareous sheath. The plants 

 are usually from 1 to 9 inches in height. (Phyc. Bor.-Am. 1911 and 191S.) 



PeniciUus pyriformis A. & E. S. Gepp, has a more pyriform-obovoid or 

 obconic head and usually a shorter stalk and the filaments of the hea.l are more 

 intertangled. The best distinguishing characteristics are, however, found in 



