THE GREEN ALGAE OP NORTH AMERICA 395 



surface ; filaments of flabellum 35-70 /x, diam., the lesser branches 

 more or less attached by short processes. W.I. 



2. U. CONGLUTINATA (Soland.) L,amouroux, 1816, p. 312; 

 Howe, 1909, p. 96, PI. II ; PI. VIII, figs. 11-13; Fronds to 10 cm. 

 high, greenish or whitish, more or less calcified ; stipe subterete, 

 above flattened and passing gradually into the cuneate base of 

 the flat, cuneate to suborbicular, uncorticated, simple or some- 

 what lobed, usually zonate flabellum ; longitudinal filaments of 

 flabellum 28-60 ^ diam., twisted and interwoven; branches of 

 the stipe cortex slender, flexuous and tortuous, loosely and 

 irregularly fastigiate, ultimate divisions digitate, subacute or 

 taper-pointed. Fla., W. I. 



To be carefully distinguished from U. cyathiformis, which is 

 sometimes quite like it in habit ; the characters of the cortex of 

 the stipe should determine in such cases. 



3. U. CYATHIFORMIS Decaisne, 1842, p. 106 ; Howe, 1909, 

 p. 96, PL III; PI. VIII, figs. 8-10 ; U. congliithiata Vickers, 

 1908, p. 24, PI. XXXII; P. B.-A., No. 1482; ? U. conglnti- 

 nata Harvey, 1858, PI. XL.C. Frond up to 15 cm. high, 

 greenish, becoming whitish, moderately calcified ; stipe sub- 

 terete, passing abruptty into the concavo-convex to cyathi- 

 form, entire or laciniate-fhnbriate, only slightly zonate, uncorti- 

 cated flabellum; longitudinal filaments of the flabellum 40-125 

 /j. diam., usually 60-100 n, nearly straight, parallel and rigid; 

 branches of the stipe cortex cymose-fastigiate, ultimate divi- 

 sions very short, apices truncate, obtuse or truncate-capitate, 

 seldom over 50 /j. long. Fig. 154. Fla., W. I. 



The cup-shaped form, from which this species has its name, is 

 sometimes hardly perceptible ; but the other characters are 

 more uniform. 



4. U. SPINULOSA Howe, 1909, p. 97 ; PI. IV, fig. 2 ; PL 

 VIII, figs. 1-7. Frond up to 8 cm. high, grayish-green, strongly 

 calcified ; stipe subterete, flattened above and passing gradually 

 into the cuneate base of the flat, obovate, longitudinally striate 

 but hardly zonate, corticated flabellum ; longitudinal filaments 

 of the flabellum 48-64 /A diam., parallel or interwoven, thickly 

 beset externally with short processes crowned with acuminate 

 spines ; branches of the stipe cortex 4-6 times dichotomous, 

 ultimate divisions taper-pointed, up to 200 // long. Bahamas. 



In habit somewhat like U. conglutinata and U. cyatliiformis, 

 but quite distinct by the well developed cortex of short, spinous 

 branchlets. 



5. U. FLABELLUM (Ell. and Sol.) Howe, 1904, p. 94; U. 



