EHODOMELACEAE. 567 



2. CHONDRIA Ag. p. p. Syn. Scand. xviii. 1817. 

 CARPOCAULON Kiitz. Phyc, Gen. 436. 1843. 

 CHONDRIOPSIS J. Ag. Sp. Alg. 2: 794. 1863. 



Apices of ultimate ramuli acute, with growing points readily visible. 

 Plants erect, mostly 540 cm. high, without rhizoids except at base. 

 Primary branches more slender than the stout well-defined 

 main axes ; plants large, mostly 15-40 cm. high, yellow- 

 ish brown when dried. 1. C. Uttoralis. 

 Primary branches rather similar to the often poorly de- 

 fined main axes. 



Plants blackish purple on drying, rather coarse, branch- 

 ing irregular. 2. C.atropurpurea. 

 Plants yellowish red or dusky red on drying, more deli- 

 cate, branching sparsely virgate. 3. C. tenuissima. 

 Plants low-cespitose, 2-3 cm. high or subrepent, with numer- 

 ous multicellular rhizoidal haptera. 4. C. polyrliiza. 

 Apices of ultimate ramuli obtuse or truncate, with growing point 



immersed and hidden in an apical pit. 



The five pericentral siphons with conspicuous saucer-shaped, 

 dome-shaped, or cup-shaped thickenings of their anterior 

 end-walls, forming regular transverse crenate lines 

 bounding the even-ended bundles of siphons and visible 

 through the cortex. 



Plants cespitose, the cushions 1-3 cm. high ; main axes 

 mostly 0.22-0.35 mm. in diameter ; apical tufts of fila- 

 ments inconspicuous. 5. C. curvillneata. 

 Plants solitary or merely gregarious, mostly 3-8 cm. high ; 

 main axes 0.40.75 mm. in diameter ; apical tufts of tri- 

 choblasts conspicuous, often 0.75 mm. or more in length, 

 becoming yellowish brown or fuscous on drying. 6. C. CoUinsiana. 

 Pericentral siphons without conspicuous thickenings of the 

 anterior end-walls (or such thickenings of only irregu- 

 lar and occasional occurrence). 



Plants pink, purple, or yellowish red ; main axes mostly 

 0.51.5 mm. in diameter ; ultimate ramuli mostly 0.35 

 0.75 mm. in greatest diameter. 7. C. daayphylla. 



Plants usually yellowish brown ; main axes mostly 0.22- 

 0.32 mm. in diameter ; ultimate ramuli mostly 0.1-0.2 

 mm. in greatest diameter. 8. C. leptacremon. 



1. Chondria littoralis Harv. Ner. Bor.-Am. 2: 23. 1853. 



Chondriopsis littoralis J. Ag. Sp. Alg. 2: 795. 1863. 

 Carpocaulon littorale Kuutze, Kev. Gen. PI. 3 2 : 399. 1898. 



Rather common on moderately exposed shores, near the low-water mark, New 

 Providence, Berry Islands, Great Bahama, Exuma Chain, Watling's Island, Marl- 

 guana, and Caicos Islands : Florida and the West Indies generally. Type from Key 

 West, Florida. 



2. Chondria atropurpurea Harv. Ner. Bor.-Am. 2: 22. pi. 18E. 1853. 



Chondriopsis atropurpurea J. Ag. Sp. Alg. 2: 801. 1863. 

 Carpocaulon atropurpureum Kuntze, loc. cit. 



In shallow water, especially in creeks and lagoons, commonly straw-colored when 

 living, Great Bahama, Great Exuma, Watling's Island, and Great Ragged Island : 

 Bermuda : South Carolina ; Florida ; and the West Indies generally. Type from 

 Charleston, South Carolina. 



3. ? Chondria tenuissmia (Good. Woodw.) Ag. Syn. Alg. Scand. xviii. 1817. 



Fucus tenuissimus Good. Woodw. Trans. Linn. Soc. 3: 215. pi. 19. 1797. 



Carpocaulon tenuissimum Kuntze, loc. cit. 



Laurencia Baileyana Mont. Ann. Sci. Nat. Bot. III. 11: 63. 1849. 



Two specimens that we refer provisionally to C. tenuissima differ consid- 

 erably from each other and from the English type of the species, in habit, 

 texture, form and size of the cortical cells, etc. 



In shallow water, Bimini and Great Bahama : Massachusetts to Florida and 

 Cuba ; Europe. Type from southern England. 



