306 Vniversitij of Californm Piihlications in Botany [Vol.8 



frequent occurrence in the maritime region, especially where fogs 

 are frequent. Only one species, however, is said to be found where 

 actually immersed at high tide and that grows upon wood. The aerial 

 species on rocks and wood are often conspicuous, forming broad 

 patches of j-ellow or deep orange-red upon the rocks or tree trunks. 

 Those visiting the shore in search of marine algae are very likely to 

 encounter some of these species. 



Trentepohlia odorata var. umbrina (Kuetz.) Harlot 



Filaments forming a more or less dense, at times pulverulent or 

 tomentose stratum, without marked distinction between prostrate and 

 erect positions, flexuous, somewhat torulose, with short branches ; color 

 green, varying to brownish or orange-red ; cells varj- ing from cylin- 

 drical to ovoid, 10-30ju. diam., 1-1. 5/i, times as long; cell wall thin when 

 young, becoming thick and lamellate with age ; gametangia spherical 

 to ellipsoid, lateral, terminal or intercalary, 20-30/a diam. ; sporangia 

 similar to gametangia. 



Growing on piles of Douglas Fir (Pseudotsuga taxifolia) along 

 high-tide level. Breakwater, San Pedro Harbor, Los Angeles County, 

 California. 



Hariot, Notes sur le genre Trentepohlia, 1889, pp. 400-403; Col- 

 lins, Green Alg. N. A., 1909, p. 319. Collins, Holden and Setchell, 

 Phyc. Bor.-Amer. (Exsicc), no. 2288. Chroolepns umbrinum Kuetz- 

 ing, Phyc. Gen., 1843, p. 283, pi. 7, f. 2. Trentepohlia umbrina var. 

 quercina Collins, Holden and Setchell, Phyc. Bor.-Amer. (Exsicc), 

 no. 662. 



One of us (Gardner) has found what certainly seems to be this 

 species growing on piles of Douglas Fir {Pseudotsuga taxifolia) along 

 high-tide level and above, but where frequently immersed in or 

 splashed by the sea water. The zone affected by the tide was of 

 green color, but above, where contact with salt water was less frequent, 

 the color was deep orange. The locality was observed on two occasions 

 several years apart, and the Trentepohlia found persisting. The 

 filaments are to be found mostly within the empty wood cells of the 

 piles. 



