104 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



and which is found floating and infertile in the course of the Gulf Stream and in the 

 6o-called Sargasso Sea, "between 20° and 45° N. and 40° W. It is rarely washed ashore 

 in New England, hut is frequently brought in hy fishing vessels. It is said that there 

 is a large mass of this sea-weed in the ocean not far from Nantucket, but there is no 

 definite information on the subject. The species in its floating form is distinguished 

 from the last by its narrower leaves, destitute of cryptostomata, its darker color, and 

 denser habit. 



Suborder* VAUCHERIEiE. 



Comprising a single genus, Vauclieria, whose characters are given 

 below. 



YATTCHEEIA, D. 0. 

 (Named in honor of Jean Pierre Vaucher, of Geneva.) 



Fronds green, unicellular, composed of long, irregularly or falsely 

 dichotomously branching filaments, monoecious or dioecious; oogonia 

 sessile or stalked, containing a single oospore ; antheridia either short 

 ovoid sacks or formed at the tips of branches, which are frequently 

 spirally twisted; antherozoids very small, with two cilia; non-sexual 

 reproduction by very large zoospores, which are covered with cilia, or by 

 motionless spores formed at the ends of short branches. 



The Vaucherice abound hoth on our coast and in inland waters, and some species 

 grow upon damp ground in gardens and meadows. They either form thick turfs of a 

 dark-green color when growing in places which are not constantly submerged, or else 

 extend in indefinite-shaped masses when growing where there is plenty of water. 

 They are generally easily recognized at sight, and are known under the microscope 

 hy the long branching filaments of a deep-green color, destitute of cross-partitions 

 except when the fruit is forming. Although very abundant on our shore, the species 

 are little known, because the specific characters depend upon the fruit. The deter- 

 mination of sterile specimens is out of the question, and , even when fruiting, dried 

 specimens are of comparatively little value. A considerable numher of species of 

 Vaucheria have been described, hut as a great part of them have been described from 

 individuals bearing the non-sexual spores only, recent writers, as Walz and Nordstedt, 

 have reduced the number of species very much hy omitting imperfectly characterized 

 forms. Nordstedt admits nineteen species in Europe. The American species have 

 never heen critically studied. Specimens should be kept in fluid rather than mounted 

 on paper, and sketches of the fruit should be made at the time of gathering. It 

 should not he forgotten by the collector that some of the species are dioecious, and 

 also that a species is not perfectly known unless the non-sexual spores are described 

 as well as the oospores. 



Y. Thuretii, Woronin, Beit, zur Kenntniss der Vaucherien, in Bot. 

 Zeit., Vol. XXVII, p. 157, PL 2, Figs. 30-32. 



Monoecious; filaments .03-8 mm in diameter, forming short, dense turfs; 

 antheridia sessile, oval, .05-7 mm broad by .10-14 mm long ; contents of 

 antheridia colorless ; oogonia either sessile or on short lateral branches, 

 obovoid or pyriform, inclined, .25-30 mm long by 20 ram wide; oospores 

 spherical, .15-18 mm in diameter, yellowish brown ; cell- wall rather thin ; 



