Characeae. 41 



Braun described a niimber of forms (some of them originally as species) 

 with which we have endeavoured as far as possible to identify the "West In» 

 dian specimens. We do not however regard these as distinct varieties but 

 rather as stages of Variation between which series of intermediates are to be 

 found. Dr. Allen described several of the forms as species but we nnder- 

 stand subsequently followed Braun in concluding that they all belonged to 

 the one species. Mr. CA B. Robinson in Bull. New York Bot. Gard. IV 

 (1906) p. 282 — 295 has kept up Braun's and Allen's species and has 

 added to the number. Nearly all the specimens we have examined appear 

 to be more or less intermediate rarely agreeing exactly with any of the 

 named forms. 



1. forma elegans. — C. gymnojjus vnr. elegans T. F. Allen Charac. 

 amer. (1879) imrt 1 t. 1; Braun Fragmente (1882) p.l89.— C. ele- 

 gans llohinson l. c. p. 283. 



Plant rather large, but slender. Branchlets 11 — 13, with 7 — 10 

 Segments, the last 1 — 4 ecorticate. Bract-cells 8—9 spreading whorled, 

 the posterior but little shorter than the anterior. Oogonia produced 

 at the first node. 



2. forma trichacantlia. — C. gymnopus var. trichacantha Braun 

 Fragmente (1882) p. 190. — C. trichacantha Robinson l. c. p. 294. 



Plaut rather large and slender. Branchlets 12 — 13 with 10 — 15 

 Segments of which the first and last are ecorticate. Spine-cells and 

 anterior bract-cells long and slender, posterior bract-cells at lowest 

 node much shorter and sometimes ventricose and inflexed. Oogonia 

 produced at the first node. 



3. forma fertilissiina, — C. gymnopus var. fertilissima Braun 

 Fragmente (1882) p. 192. — C. fertilissima Robinson l. c. p. 286. 



Plant small slender. Branchlets 12 — 13 with 9—10 segments, 

 the last 1 — 3 ecorticate. Anterior 2 pairs of bract-cells longer than 

 the oogonium, next pair shorter, posterior usually quite short. Oogonia 

 almost cylindrical produced at the first node. 



4. forma incoiistaiis. — C. inconstans Kuetz. Tab. Pliyc. (1857) 

 VII p. 28 t. 70 f. 2. — C Ocrstedianä et Cruegeriana Braun Monatsb. 

 Berl. Akad. 1858 p. 367—8. — C. gymnopus var. inconstans Braun 

 Fragmente (1882) p. 193. 



Plantrather small, weak. Branchlets about 11, with 7 — 10 

 segments, the lowest not shortened as in the other forms (except 

 sometimes in form 9), the following 1 — 3 usually corticate, sometimes 

 all ecorticate. Anterior pair or two pairs of bract-cells longer than 

 the oogonium, others shorter. Oogonia produced at the lowest node. 



5. forma Bertcroi. — C. indica Bertcro in Spreng. Syst. Veg. IV 

 (1827) p. 346. — C. polyphylla var. guadeloupensis Brairn in Boston 

 Journ. Nat. Eist. vol. V (1845) p. 264. — C. polyphylla vars. Berteroi 



