THE MAKIXi: ALG/E OF NEW ENGLAND. 41 



MONOSTROMA, (Thuret) Wittrock. 



(From /ioi'Of, single, and arpufxa, a bed.) 



Fronds inombranaceous, consisting of a single layer of cells, whicli arc 

 either pareiu'liymatous or separated from one another by more or less 

 Jelly. 



As (UTiDoil l)y Thmvt, Monontroma dilTored from Ulva in IkivIiil; the cells einbeddt'd 

 in jelly rather than arrani::ed in the nsnal form of i)arenchymatous tissue. Wittrock 

 ineludrs in the ^enns all the Ulviv consistinj; of a sini^le layer. In moat of the species 

 the fron»l is at lirst sack-shape, but soon ruptures, the s«'^ments be injj; composed of one 

 layer of cells. The basal cells are prolonged downwards, but they become more or 

 less circular in the ui)per i>art. 



M. ruLcniii M, n. sp. 



Fronds membranaceons, fascicnlate, light green, lanceolate or cnneate- 

 lanceolate, attennated at the base, margin crisped, two to twelve inches 

 long, two inches broad, substance very delicate, about .OOG'""' in thick- 

 ness, cells irregular, more or less sinuous, intercellular substance small. 



Watch Hill, Conn., Prof. Eaton ^ Gloucester, Mass., Mrs. Bray ; Port- 

 land, 3Ie., Mr, C. B. Fuller. Spring. 



A beautiful and apparently not uncommon spring plant of New England, dis- 

 tinguished by its outline and delicate substance. When fully grown the fronds are 

 most freiiuently attenuated at the base and rather obtuse at the summit. When young 

 they are lanceolate, an«l seem to bo always plane, never saccate, as in the next species. 

 The color is a delicate green, and the plant cannot easily be removed from the paper 

 on which it is pressed. This species has sometimes been distributed as Ulva Linza, to 

 which it bears more or less resemblance in shape. 



M. Grevlllei, Wittrock. ( Ulva Lactuca^ Grev. no7i Linn. ; ITarv. Phyc. 

 Brit., PI. 243, and Xer. Am. Bor., Part III, p. GO. — Enteromorpha Gre- 

 rllld, Thuret.) 



Frond at first saccate, then split to the base into irregular segments, 

 color light green, segments plane, unequally laciniate, frond about 

 .012°^ thick, cells angular, intercellular substance small. 



Boston Bay (Ner. Am. Bor.); Maiden, Mass., Mr. Collins; Ives 

 Point, Conn., Mr. F. W. Hall; Europe. Spring. 



A common spring species of the Atlantic shores of Europe, but apparently not so 

 common in New England. The cells of this species vary considerably, and, in some 

 specimens the intercellular gelatinous substance is tolerably prominent. 



M. Blytii, (Aresch.) Wittr. {Ulva Blytii, Aresch., Phyc. Scand., p. 

 18G, PI. K) f/.—M. /i/j/r^V, Wittrock, Monog. Monostr., p. 49, PI. IV, Fig. 

 11.) 



Frond nuMnbranaceous, subcoriaceous, dark green, irregularly cleft, 

 margin cri.sped, .028-40"'"' in thickness, cells angular, closely packed, 

 intercellular substance small. 



Exs.— Xordstedt & Wittrock, Alg. Scand., Xo. 11: Alg. Am. Bor., 

 Farlow, Anderson & Eaton, Xo. 98. 



