PDF file (text) - Cryptogamic Botany Company

Recommendations

Info

44 THE MARINE ALGÆ OF NEW ENGLAND. species approaches Ulva clathrata. Innumerable varieties have been made of the various forms of this species, but an enumeration of them is quite uncalled for in this place. Ulva clathrata, Ag. “Frond tubular, filiform, several times branched, branches attenuate at the apex, often very fine, cells arranged in rows.” (Le Jolis, Liste des Algues Marines de Cherbourg.) As usually defined by algologists, Ulva clathrata differs from U. compressa principally in the smaller size of the branches, a character by no means constant. We quote the specific distinctions as given by Le Jolis, l. c., which express more clearly than the descriptions of other writers the relations between the species: “I think they (the specific characters) are to be found, first, in the general form of the fronds, which, broadened at the summit in the different varieties of Ulva Enteromorpha, are, on the contrary, much attenuated at the extremity in Ulva clathrata. Secondly, in the ramification. While Ulva compressa and intestinalis are rather proliferous than branching in the true acceptation of the word—their branches being ordinarily of such a character that when they are given off from the lower part of the frond there does not exist, so to speak, any principal axis, or when borne towards the extremity of the frond reduced to simple proliferations; in Ulva clathrata, on the contrary, there exists a well-marked ramification, the fronds or primary axes bearing numerous secondary branches, which in their turn produce branchlets of an inferior order.” Of the species, as defined by Le Jolis, there are several varieties common on our coast, principally to be distinguished by the fineness of the branches and more or less complicated ramification. The variety Agardhiana of Le Jolis (Enteromorpha Linkiana, Grev.), rather coarse and rigid, is common in shallow water, as is also the form called by Harvey Enteromorpha ramulosa. The var. Rothiana forma prostrata is found in a ditch at Maiden, Mass. ULVA HOPKIRKII, (McCalla) Harv., Phyc. Brit., Pl. 263. Frond capillary, excessively branched, ramuli ending in a single row of cells. Greenport, L. I., Mr. Hooper; Gloucester, Mass., Mrs. A. L. Davis; Europe. A beautiful species, looking much more like a fine Cladophora than an Ulva. It is in most cases easily recognized by its tenuity and light-green color. It grows in large tufts on other algæ and is about eight or ten inches long. It is by no means certain that this species should not be regarded as an extreme variety of U. clathrata in spite of the fact that the branches usually end in a single row of cells. ULOTHRIX, (Kütz.) Thur. (From υλη [ule], a forest, and θριξ [thrix], a hair.) Filaments grass-green, soft and flaccid, unbranched, at first forming tufts attached at the base, afterwards becoming more or less entangled, cells never long in proportion to their diameter. The genus Ulothrix here includes all the unbranching marine Chlorosporeæ of a delicate <strong>text</strong>ure, and embraces the species included by Harvey in the genus Hormotrichum of Kützing, which can hardly be kept distinct from Ulothrix, an older genus of Kützing. When young the species of the genus are attached at the base and unbranched, but in some cases, when old, the filaments are twisted together, and it is not always easy to find the point of attachment.
REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 45 The genus is too nearly related to Chætomorpha, from which it differs in substance, the filaments being more or less gelatinous in Ulothrix and rigid in Chætomorpha. Of all the filamentous marine Chlorosporeæ the species of Ulothrix are best adapted for the study of zoospores. The conjugation of zoospores in Ulothrix zonata, a fresh-water species, has been very fully described by Dodel-Port in Pringsheim’s Jahrbücher, Vol. X. U. FLACCA, (Dillw.) Thuret. (Lyngbya flacca and Carmichaelii, Harv.‚ Phyc. Brit., Pl. 300 and 186 a.—Hormotrichum Carmichaelii, Harv., Ner. Am. Bor., Part III, p. 90.) Filaments fine, lubricous, greenish yellow, one to three inches long, at first tufted, then entangled and forming strata of indefinite extent filaments .014-30 mm in diameter, becoming moniliform, cells .003-12 rmm long, generally narrow, discoidal. Eastport, Maine., on stones and Rhodymenia, August; Nahant, Mass., Mr. Collins, spring; Isles of Shoals, N. H., Mrs. Davis; Europe. A species most luxuriant in the spring, but also found in summer. The form found at Eastport was the entangled stage which is common on wood-work at low-water mark. U. ISOGONA, (Engl. Bot.) Thuret. (Conferva Youngana, Harv., Phyc. Brit., Pl. 328.— Lyngbya speciosa, 1. C., Pl. 186 b.—Hormotrichum Younganum, Ner. Am. Bor., Part III, p. 89.—Urospora penicilliformis, Aresch. in part.) Filaments fine, yellowish green, one to three inches long, at first tufted, afterwards forming strata, filaments .036-58 mm in diameter, moniliform, cells .015-50 mm long, from cuboidal becoming ovate, constriction at nodes marked. New York, Harvey; Ives Point, Conn., Mr. Hall; Gloucester, Mrs. Davis; Nahant, Mr. Collins; Europe. Spring. Distinguished from the last by its greater size and by the marked constriction between the cells at maturity. Apparently common on wood-work. Whatever name we may give to this species, it is the same form which is common in the northern part of Europe in spring and summer. It is the Hormotrichum Younganum of British authors, and the U. isogona of the French. It is the species referred by Areschoug, Observationes Phycologicæ, II, Act. Reg. Soc. Scient., Ser. Ill, Vol. 9, to Conferva penicilliformis, Roth, and made by him the type of the genus Urospora. Areschoug unites under the single species U. penicilliformis the following species of Phycologia Brittanica: Lyngbya speciosa, L. Carmichaelii, L. Cutleriæ, L. flacca, and Conferva Youngana. In the present ease we have kept U. flacca and U. isogona distinct, but agree with Areschoug in uniting U. speciosa with U. isogona. Perhaps a further acquaintance with the species might lead us to unite the present two species under Areschoug’s name. The Hormotrichum speciosum of Baton’s list of Eastport algæ belongs to another genus. The H. boreale, l. c., is unknown to me. U. COLLABENS, (Ag.) Thur.? (Conferva collabens, Harv.‚ Phyc. Brit., Pl. 327.— Hormotrichum collabens, Kütz Spec. Alg.‚ p. 383.) Filaments tufted, two to six inches long deep green, cells from .05-
Page 1 and 2: I.-THE MARINE ALGÆ OF NEW ENGLAND.
Page 3 and 4: REPORT OF THE COMMISSIONER OF FISH
Page 43: REPORT OF THE COMMISSIONER OF FISH
Page 95 and 96:
REPORT OF THE COMMISSIONER OF FISH
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
show all

PDF file (text) - Cryptogamic Botany Company

Create successful ePaper yourself

Delete template?

Save as template?