1925] Setchell-Gardner: Melanophyceae 657 



J. G. Agardh, Sp. Alg., vol. 1, 1848, p. 101. 



The genus was founded by J. G. Agardh on Ulva Atomaria Wood- 

 ward (Linn. Trans., vol. 3, 1797, p. 53). U. Atomaria was discovered 

 by Mr. Lilly Wigg on the beach at Yarmouth, England. Since its 

 discovery, it has been associated with at least the following genera : 

 Dictyota, three different species, Zonaria Atomaria, Padina, two 

 species, Stypopodium Atomaria and Ulva serrata. While the genus 

 Taonia is to be distinguished from Zonaria by its usually more delicate 

 tissues, its absolute lack of a midrib (Zonaria. being subcostate), and 

 by a greater tendency to have its reproductive bodies in concentric 

 lines, nevertheless there are difficulties in exactly diagnosing it. In all 

 the species of Zonaria, the reproductive bodies are, at least at maturity, 

 superficial, while in the species of Taonia, they are partially embedded 

 in the frond. 



Taonia Lennebackerae Farlow 

 Plate 35, figs. 9, 10, and plate 96 



Fronds arising from a slightly stupose base, 1-2 dm. (up to 3 dm.) 

 high, variable in width; segments mostly broadly cuneate from near 

 the base of the fronds, unevenly divided at the outer end into several 

 lobes, often deeply lacerated ; color when young olive, dark brown in 

 older specimens; cells of the interior 3-4 layers, angles considerably 

 rounded, slightly elongated longitudinally ; cells of the cortex mostly 

 arranged in longitudinal rows, 1.5-3 times as long as broad ; reproduc- 

 tive cells mostly scattered promiscuously and profusely on both sides 

 of the frond, at times vaguely in concentric lines. 



Growing on rocks in the upper subittoral belt. Southern Cali- 

 fornia. 



Farlow, in Farlow, Anderson and Eaton, Alg. Exsicc. Amer.-Bor., 

 no. 160 (n-omen nudum) ; J. G. Agardh, Anal. Alg. Cont. I, 1894, 

 p. 30 (description) ; Collins, Holden and Setchell, Phyc. Bor.-Amer. 

 (Exsicc), no. 327; Tilden, Amer. Alg. (Exsicc), no. 337. 



The type locality of this species is Santa Barbara, California. The 

 type specimens were contributed by Miss Lennebacker, of Santa 

 Barbara. The California species seems more delicate than the Euro- 

 pean, with never a sign of a stupose base and with the fruit dots 

 usually scattered, although at times in undulate and indistinct concen- 

 tric lines. According to J. G. Agardh, the cortical cells are shorter 

 than in other species of the genus (1.5-3 times longer as contrasted 

 with 3-4 times longer in surface view). Our plant is certainly less 



