MARINE ALG OF BEAUFORT, N. C. 433 
The species is distinguished from C. decorticatum by its more rounded, more densely branched 
thallus, and sometimes by its smaller utricles. The extremes of these species are yery different in 
appearance, but they are connected by numerous intermediate forms so that it is often very difficult to 
decide to which species a given specimen should be referred, especially since the utricles may ay 
greatly in size, and the thallus is always more or less flattened below the dichotomies. 
2. Codium decorticatum (Woodward) M. A. Howe. Pl. LXXXYV, fig. 2. 
Ulva decorticata, Woodward, 1797, D. 55. 
Codium elongatum, Agardh, 1822, p. 454. 
Codium elongatum, De Toni, 1889, p. 496. 
Codium elongatum, Collins, 1909, p. 388. 
Codium decorticatum, Howe, 1911, p. 494. 
Codium. decorticatum, Collins, 1912, p. 99. 
P. B.-A. Nos. 627 (C. elongatum), 2017. 
Frond dichotomously branched, often much elongate, younger divisions terete, older ones flattened, 
especially below the dichotomies, being there distinctly cuneate; utricles obovate-clavate, 300 to 400 
mic. in diameter(?), five to six times as long as the greatest diameter. 
North Carolina to Florida; West Indies; Lower California, Mexico; South America; Europe; Africa. 
Beaufort, N. C.: Abundant on Bogue Beach after winds; occasional in Beaufort Harbor in earlier 
years, becoming more abundant in later years; abundant on rocks of Fort Macon jetties, July, 1909; and 
very abundant in harbor off Duncan breakwater and north of laboratory, September, 1909. Pawleys 
Island, near Georgetown, S. C.: Abundantin bay near inlet, August, 1909. 
This is the northern limit of the species reported for North America. ; 
The species is distinguished from C. tomentosum by the greater flattening, the more elongate, less 
densely branched frond, and sometimes by the larger utricles. The younger plants resemble C. tomen- 
tosum, but the flattening is marked in older plants; in some cases all parts except the younger tips are 
quite broadly cunedte. As, however, all plants of both species are more or less’ flattened below the 
dichotomies, and numerous intermediate forms are found, it is often difficult to determine on this basis 
to which species a given specimen should be referred. One specimen found at Beaufort had three main 
divisions, two of which were flattened like C. decorticatum, while the third resembled C. tomentosum. 
Dried specimens are particularly unreliable in this respect, since in these the amount of flattening may 
be largely due to the amount of pressure to which the plants were subjected during drying. 
The size of the utricles furnished no criterion for distinguishing the plants of this region. While 
those on the coarsest, widest specimens are wider, those on other individuals having the form of C. decor- 
ticatum are narrower than many of those on individuals having the typical form of C. tomentosum. 
If the two extreme forms found at Beaufort grade into each other in other localities as much as they 
do at this place, it may be questioned whether the present species is not merely a large form of C. tomen- 
tosum. On the other hand, however, the fact that it was first found at Beaufort on Bogue Beach and 
only in later years made its appearance in the harbor, indicates that it is a distinct species and that it 
established itself in this region during the period of this study. It seems, too, to appear here later in 
the spring and to disappear earlier in the fall than C. tomentosum. On this basis the intermediate forms 
may possibly be ascribed to hybridization. 
This species may grow toa large size. One specimen collected on a jetty at Fort Macon had a length 
of r meter and a width of 5 cm. below its widest dichotomy. 
Genus 2. Udotea Lamouroux. 
Udotea, Lamouroux, 1812, p. 186. 
Frond arising from a mass of rhizoids, differentiated into stipe and flabellum; stipe 
erect, with distinct cortex, terminating in a fan-shaped, more or less’ distinctly zonate 
flabellum, consisting of continuous, branching filaments, with more or less numerous 
short branches attached to each other by short processes and sometimes developing 
laterally into a more or less definite cortex; calcification more or less complete; repro- 
duction unknown. 
