THE ALGAE OF BERMUDA. 107 



sun or air, the color darkens, sometimes becoming nearly black. But 

 if the plant has grown where it is exposed to the full sunshine or if it 

 has been exposed long to the air, the red becomes lighter and clearer, 

 and later takes on a yellow shade. Exposure to the air for several 

 days, if not in full sunshine, gives handsome color without disinte- 

 grating or decomposing the plant, if quite fresh when collected. It 

 occurs in all sizes from 5 to 50 cm. high, and varies much in diameter 

 of frond, frequency and regularity of branches, and especially as to the 

 frequency, position and form of the conical or spinous ramuli. In 

 the typical form these ramuli are arranged in whorls, distinctly 

 separated, but forms occur, especially in old and large individuals, 

 in which this whorled arrangement is hardly perceptible. The same 

 differences occur in this species as found on the Florida coast, where it 

 is common. At some stations in Bermuda a form occurs which we 

 have not seen elsewhere; the frond is not over 10 cm. high, is relatively 

 slender, but is so densely and so repeatedly branched that no trace of 

 regularity is seen. This form was collected by Wadsworth in 1890, 

 and has been found by us each year we have collected here. The 

 American plant was described by Agardh, 1822, p. 271, as Sphaero- 

 coccus isiformis; J. G. Agardh, 1847, p. 16, proposed the new genus 

 Eucheuma, including this and other species of Sphaerococcus, and the 

 name has been continued since that time. Comparing the original 

 description of Sphaerococcus isiformis with the species following, S. 

 spinosus, the only distinctions of importance are, first that the former 

 is described as "cartilagineo-gelatinosa" the latter as "gelatinoso- 

 cartilaginea"; second, the former "papillulis ramorum verticillatis," 

 the latter "papillulis solitariis, vel binis ternisve." The question of 

 the distinctness of the two species was raised by Sonder, 1871, p. 60; 

 under E. spinosum he notes that he found it with long, naked branches, 

 also beset with papillae, either scattered or whorled. This alga is 

 sold as an article of food in eastern countries, and most of the speci- 

 mens that had then reached Europe were coarse forms obtained in 

 the markets. J. G. Agardh, 1876, p. 601, referring to Sender's criti- 

 cism, says "Quae potissimum conveniunt, E. spinosum atque E. isi- 

 forme, stadio fructifero omnino diversae obvenerunt." But we find 

 on E. isiforme fruit of the character attributed by him to E. spinosum, 

 as well as that attributed to E. isiforme. Later, 1892, p. 12, in a 

 revision of the genus, he uses vegetative characters, giving as the 

 reason that the cystocarps were unknown to him on many of the 

 species. Under E. spinosum he says "Icon Turneri tab. IS pro suo 

 tempore egregia." E. isiforme he considers as represented by Harvey's 



