PDF file (text) - Cryptogamic Botany Company

Recommendations

Info

60 THE MARINE ALGÆ OF NEW ENGLAND. found on the shores of California. It is very widely diffused, being found in nearly all seas. B. hypnoides, which occurs at Key West, passes almost insensibly into B. plumosa, but the typical B. hypnoides is not known in New England. ? DERBESIA, Sol. (Named in honor of Prof. Alphonse Derbes of Marseilles.) Fronds green, simple or slightly branching, unicellular, or sometimes with crosspartitions at the base of the branches; fructification consisting of ovoidal sporangia containing zoospores, which are of large size and have a hyaline papilla at one end, at the base of which is a circle of cilia; oospores unknown. The genus Derbesia was founded by Solier on two Mediterranean species, D. marina and D. Lamourouxii. The position of the genus is. doubtful. The Derbesiæ resemble in habit the more delicate species of Vaucheria and Bryopsis, and like them are often unicellular, but it is, however, not uncommon to find at the base of some of the sterile branches a short cell, separated by a wall both from the branch above and the main filament below. A similar cell is always present at the base of the sporangia, and the same cell is found in some species of Vaucheria. Derbesia differs from Bryopsis in having zoospores provided with a circle of cilia, borne around the base of a terminal hyaline papilla as in Œdogonium. It differs from Vaucheria in not having oospores, so far as is known. The zoospores of Derbesia, according to Solier, germinate at once and are apparently of a non-sexual character, so that we may expect that hereafter either oospores or conjugating zoospores will be found. As we have said, the zoospores bear a striking resemblance to those of Œdogonium, and perhaps the relationship to the last-named genus is closer than has usually been supposed. In this connection it should be mentioned that, in the formation of the cells sometimes found at the base of the branches, the cell-wall ruptures in the same way as in Œdogonium, and if we do not have the same rings forming a cap at the end of the cells as in Œdogonium it may be because in Derbesia the formation of new cells is very limited. D. TENUISSIMA (De Not.), Crouan. (D. marina, Solier, Ann. Sci. Nat., 3 série, Vol. VII, p. 158, Pl. 9, Figs. 1-17.—Bryopsis tenuissima, De Not., Fl. Capr.—D. tenuissima, Crouan, Florule du Finistère, non D. marina, Crouan, Algues Marines du Finistère, No. 398.—Chlorodesmis vaucheriæformis, Harv., Ner. Am. Bor., Part III, p. 30, Pl. 40 c.) Pl. IV, Fig. 4. Filaments tufted, bright green, one to two inches long, .04 mm in diameter; branches few, erect, constricted, and often with a cuboidal cell at the base; sporangia on short branches, ovoidal or pyriform, .09-.12 mm broad by .20-.30 mm long, resting on a cuboidal basal cell; spores large, few, about 15 in number. Forming tufts on algæ. Eel Pond Bridge, Wood’s Holl, Mass.; Key West; Europe. We have found this species but once on our coast, in May, 1876. With us it is apparently rare, but the species is not uncommon in some parts of Europe, especially on the shores of the Mediterranean. Our form is very well developed and the sporangia are rather longer than in the European specimens which we have seen.
REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 61 SUBORDER PHÆOSPOREÆ. Reproduction by means of olive-brown zoospores which have two laterally attached cilia; sporangia of two kinds—unilocular, containing a large number of zoospores, and plurilocular, compound sporangia, each cell of which contains a single zoospore; conjugation of zoospores known in a few species; marine plants, of an olive-brown color, whose fronds vary greatly in structure, but which all agree in reproducing by zoospores. A large group, first correctly defined by Thuret. Previous writers had regarded the structure of the frond to the exclusion of the organs of reproduction, and the species here included were placed in different orders. In the Nereis they were placed partly in the Dictyotaceæ, Sporochnaceæ, Laminariaceæ, Chordariaceæ, and Ectocarpaceæ. The four last orders have been kept as families, but the true Dictyotaceæ are a distinct order. All the olive-brown sea-weeds of New England, except the rock-weeds, belong to the present suborder. In no order of plants do the species vary so widely in habit as in the present. A large number, as the Ectocarpi, are filamentous and resemble in habit the Cladophoræ. The Laminariæ have expanded flat fronds, and in Macrocystis and Egregia, the most highly organized of the order, there are stems, distinct leaves, and air-bladders, and in Egregia special fructiferous leaflets. Many of the species are of microscopic size, but Macrocystis grows to be several hundred feet long. SPHÆNOSIPHON, Reinsch. (From σφην [sphen], a wedge, and σιφων [siphon], a tube.) Fronds formed of single cells placed side by side so as to form a more or less coherent mass; cells pyriform-cuneate or oblong-elliptical; contents of cells transformed into a number of very small spherical bodies (zoospores?). In the Contributiones ad Algologiam et Fungologiam, Reinsch places the genus Sphænosiphon, of which he describes nine species, in the order Melanophyceæ. One of the species occurs in fresh water and the rest are marine. They all form minute spots on other algæ, and consist simply of cells placed side by side, the whole forming a thin membranous expansion. If the small bodies described and figured by Reinsch in the interior of the cells are really zoospores, and if the cells themselves are olive-brown, we must regard the genus Sphænosiphon as the lowest of the Phæosporeæ. The development of the zoospores has not been observed, and as Reinsch describes the color of some of the species as bluish green and rose-colored, we must consider the position of the genus to be in doubt. Species of Sphænosiphon are not unfrequent on our coast, but they have not yet been sufficiently studied. Those which we have seen are more like the Cyanophyceæ than the Phæosporeæ in color. The following descriptions, which may apply to some of our species, are taken from Reinsch, l. c. S. SMARAGDINUS, Reinsch, l. c., Pl. 35, Fig. 4. Cells pyriform or broadly cuneiform, rounded at the apex, prolonged at the base into a hyaline pedicel; cells .0168-333 mm long, .0084-112 mm broad at apex, .002 mm at base; color bluish green; base hyaline. On Plocamium coccineum, Labrador. On Polysiphonia, Anticosti. S. OLIVACEUS, Reinsch, l. c., Pl. 36, Fig. 2 a. Cells pyriform or cuneiform, broadly rounded at apex, contracted at base; color olive-green; cells .013- 24 mm long, breadth .0096-168 mra . On Ceramium rubrum, Anticosti and Labrador. S. ROSEUS, Reinsch. Cells broadly ellipsoidal, placed loosely together, and surrounded by a thick hyaline mucus; rosecolored; .0041-50 mm long, .004-5 mm broad. On zoophytes, Labrador.
Page 1 and 2:
I.-THE MARINE ALGÆ OF NEW ENGLAND.
Page 3 and 4:
REPORT OF THE COMMISSIONER OF FISH
Page 5 and 6:
Page 7 and 8:
Page 9 and 10: REPORT OF THE COMMISSIONER OF FISH
Page 59: REPORT OF THE COMMISSIONER OF FISH
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?