77 



Penicillus dumetosus J. G. Agardh Till Alg. Syst. V. 1887. p. 61. 



Penicillus dumetosus Murray in Journ. of Bot. XXVII. 1889. p. 238 (pro parte). 



Penicillus clavatus Murray loc. cit. 



Penicillus dumetosus De Toni Syll. Alg. I. 1889. p. 501. 



Penicillus dumetosus Collins Green Alg. N. Amer. in Tufts College Studies II. [909. p. 392. 



Hab. ATLANTIC. No locality, Herb. Laniouroux ! (type of Nesea dumetosa Lamx.). — Bahamas, 

 F. JA Rayner, in Herb. Mus. Brit.! -- Bahamas, Bemini Harbour, April 17. 1904, M. A. 

 Howe ! - - Florida, Farlow in Mus. Bot. Copenhagen ! — Florida, Old Rhodes Key, Curtiss ! 

 — Florida, Boca Chica Key, Southwick, in Herb. Collins! — Key West, Harvey\ — 

 Florida, Caesar 's Creek, south of Elliott's Key, in mangrove mud near low water mark, 

 March 31, 1904, M. A. Howe n° 2952! in Herb. Mus. Brit. — Jamaica, Manchioneal, Pease 

 and Butler in Phyc. Bor.-Amer. n" 769 pro parte in Herb. Mus. Brit. ! — Antilies, Voyage 

 du Cap. Baudin, Herb. Mus. Paris! • ■ Antilles (sub nom. "A r . pyramidalis Lmx.") in 

 Herb. Decaisnel — Anguilla, W. R. Elhott\ — Guadeloupe, St. Martin (Lac Simpson), 

 dans Ie sable, presqu'au rivage (eaux troubles tres salins), Mazé n° 166 sub nom. "Penicillus 

 clavatus" Crouan ! — Guadeloupe, Moule (brisante de la Couronne) Mazé 88, i«e sér. !, 

 1074!, 1075! (all three sub nom. " Penicillus longiarticulatus Crouan"). 



The largest and coarsest species of the genus. Stipes very variable, 2.5 — 8.0 cm. long 

 and 5 — 15 mm. in diameter, often branched, thickened upwards generally compressed, with 

 dull, sometimes rough, calcified surface, which is seen to be caespitoso-papillose under microscope. 



Capitulum subglobose, usually green (or faded) when dry, attaining a diameter of 

 1 5 cm. or more. 



Filaments of capitulum dichotomously branched mostly in alternating planes, sometimes 

 trichotomously branched, loosely spreading, usually flaccid and thinly calcified, collapsed and fiat 

 when dry, 400 — 800 p. or more (usually 500 — 650 fjt, in diameter when terete), mostly attaining 

 a length of 4 — 8 cm. or more, being about as long as the stipes. 



Filaments of stipes bearing lateral appendages 3 — 5 times dichotomously divided and 

 terminated by blunt dactyline apices. [Fig. 156 — 159]. 



Penicillus dumetosus in its representative form (fig. 156) is the most clearly marked 

 species of the genus. The stipes is often branched and generally more or less compressed ; 

 the filaments of the capitulum are thinly calcified and are long, broad and flaccid (in dried 

 specimens they are green or faded), rarely if ever shewing beadlike constrictions. It varies 

 very much in length of stipes, size of capitulum and diameter of filaments ; but as a rule the 

 main characteristics just enumerated hold good and serve to distinguish all representative forms 

 without difficulty. 



Lamouroux's type of Nesea ditmelosa, kindly leut to us by Prof. Lignier, is a small 

 specimen (fig. 157). lts stipes is short and thick, and the filaments flaccid and rather narrow, 

 400 — 500 ij. (rarely 550 p), though described by Lamouroux as being more than 1 mm. in 

 diameter (Hist. Polyp. Corall. Flex. 1816. p. 258. tab. VIII, fig. 3). There is however no 

 doubt as to the identity of Lamouroux's plant with P. dumetosus as commonly accepted. 

 Lamouroux's figure is a bad one ancl apt to be misleading. The comal filaments are represented 

 with Cliylocladia-Wke joints ; however the general outline of the figure agrees with Lamouroux's 

 type-specimen, though the drawing has been reversed in printing. 



