1920] Setchell-Gardner : Chlorophyceae 157 



5. Bryopsis Lamour. 



Thallus unseptately coenocytic, much branched ; chromatophores 

 numerous small disks, each with one pyrenoid ; the axis producing 

 rhizoids below and branches above both of unlimited and limited 

 growth ; in the latter large, 2-ciliated, green, female gametes, and on 

 separate individuals, smaller, brown, 2-ciliated male gametes are 

 formed; by the union of the two a zygote is fonned germinating 

 immediately. 



Lamouroux, Observ. sur la physiol. des alg. mar., 1809, p. 333, 

 Mem. sur trois nouv. gen. de la famille des alg. mar., 1809a, p. 133; 

 Collins, Green Alg. N. A., 1909, p. 402, 



The above description, taken largely from Collins, expresses the 

 technical characteristics of the family and of the genus Bryopsis. 

 In this genus the gametes are produced in the branchlets of limited 

 growth which are little changed, but are shut off from the axis on 

 which they are borne when they are transformed into gametangia. 

 The genus contains about twenty-five species and inhabits warmer 

 waters, but a few species proceed northward into decidedlj^ cold 

 water, e.g., B. plumosa (Huds.) J. Ag. being credited even to the 

 icy waters of Baffin Bay. Most of the species have wonderfully sym- 

 metrical fern-like fronds of a beautiful dark green which, when spread 

 out on paper, adhere closely to it and produce a very pleasing picture. 

 Our Pacific Coast species are nowhere common, and are in need of 

 more careful study to determine their habits of growth and reproduc- 

 tion, as well as their specific differences and identities. 



The species of Bryopsis present problems of determination of 

 exceeding complexity and difficulty. The specific limits do not seem 

 to be at all well ascertained and the actual identity and limits of the 

 described species must remain uncertain until some monographer, 

 with ample facilities and patience, shall have unusual opportunities 

 for study and illustration. Much remains to be determined as to the 

 stability of the various characters of these plants. A preliminary 

 study leads us to believe that many characters, even of minor morpho- 

 logical importance, may prove stable and suitable for use in distin- 

 guishing species. The general habit, the number of orders of branch- 

 ing, the distinctness or lack of it of the "plumes," or feather-like 

 divisions, the distichous, tetrastichous, or polystichous arrangement 

 of the ultimate branchlets, or "pinnules," are characters now gen- 

 erally employed. We suggest also comparison of the exact shape and 



