PDF file (text) - Cryptogamic Botany Company

Recommendations

Info

164 THE MARINE ALGÆ OF NEW ENGLAND. base, from which radiate the sporiferous filaments, pericarp thick and connected with the placenta by slender filaments. A genus containing not far from forty species, none of which really deserve the generic, name, for they are usually coarse and often decidedly cartilaginous. The specific distinctions are principally derived from the branching, which in the present genus is very variable. Some of the species, as G. lichenoides, are used as food. G. MULTIPARTITA, J. Ag.; Phyc. Brit., Pl. 15. Fronds purplish red, four to twelve inches long, compressed or submembranaceous, deeply cleft vertically in an irregularly dichotomous or palmate manner, divisions linear wedge-shaped, acute; cystocarps large, conical, scattered over the frond. Var. ANGUSTISSIMA, Harv. Fronds narrow, nearly filiform below, compressed above, irregularly dichotomous, the apices frequently palmately divided. On stones and on muddy bottoms below low-water mark. Massachusetts Bay, Harvey, and common from Cape Cod southward; Europe; California. A coarse and variable species, which is generally of a dingy purple color. The limits of the species are difficult to fix. Occasionally one finds with us specimens as broad as the common European form, but on the coast of California, and especially of Florida, one finds forms which look like large Rhodymeniæ. Most of our specimens are narrower than the type, and the var. angustissima of Harvey, it must be confessed, has more the habit of G. compressa than of G. multipartita. At Orient we have seen what we supposed was G. confervoides, but unfortunately our specimens were misplaced. SUBORDER RHODOMELEÆ. Fronds usually filiform and branching, sometimes membranaceous or (in exotic genera) reticulate; antheridia ovate or lanceolate in outline, formed by the transformation of monosiphonous branchlets, occasionally covering the surface of discoidal branches; tetraspores generally tripartite, borne either in localized portions of the fronds or in specially modified branches (stichidia); cystocarps external, with a distinct ovate or urceolate conceptacle or pericarp, spores pyriform, borne on short stalks given off from a basal placenta. The largest suborder of the Florideæ, and one containing many of the most beautiful sea-weeds. The suborder is mainly characterized by the cystocarpic fruit, which is external, and has the spores borne separately on short stalks which arise from a placenta which surrounds the carpogenic cell at the base of the conceptacle. In the Dasyæ, however, the filaments which bear the spores branch and fill the larger portion of the conceptacle, but we have not thought it advisable to separate them as a suborder. The antheridia, except in the genus Chondriopsis, where they assume a peculiar shape, form ovate or siliculose tufts, generally developed from monosiphonous branchlets or rather hairs. The position of the tetraspores varies in the different genera. In some cases the branchlets become broadly ovate and the tetraspores are
REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 165 borne in parallel rows. Such collections of tetraspores are called stichidia. The fronds in the present suborder vary greatly. In the more beautiful genera of tropical regions they are in the form of complicated net-works or in membranes in which the cells are arranged in regular order, but in the majority of the genera the fronds are filiform and branching and generally beset, at least at some seasons, with delicate hairs. In most of the genera represented on our coast the fronds have a polysiphonous axis, that is, on cross-section there is seen to be a central cell surrounded by a circle of large cells, and in longitudinal sections there is a central filament composed of large cells, and on each side a lateral filament whose cells correspond in length to those of the central filament, the upper and lower walls of the three cells forming two parallel lines. Fronds flattened ................................................................Odonthalia. Fronds filiform .....................................................................................1 1. Tetraspores borne in the smaller branches..................................2 Tetraspores borne in stichidia ......................................................4 2. Superficial cells small, irregularly placed ....................................3 Superficial cells, at least in the younger branches, in transverse bands Polysiphonia. 3. Branches filiform throughout ..................................... Rhodomela. Ultimate branches club-shaped, much attenuated at base. Chondriopsis. 4.Fronds beset with monosiphonous branchlets .......................Dasya. Fronds without monosiphonous branchlets, superficial cells quadrate Bostrychia. CHONDRIOPSIS, J. Ag. (From χονδρος [chondros], cartilage, and οψις [opsis], an appearance.) Fronds brownish red, terete or subcompressed, pinnately decompound, branches virgate, much constricted at the base, composed of a monosiphonous axis surrounded by a few (4-6) siphons and surrounded by secondary siphons, cortex of small polygonal cells; antheridia borne in short disk-like branchlets covering both surfaces except at the margin; tetraspores tripartite, in club-shaped branchlets; cystocarps sessile, ovate, with a distinct carpostome, spores pyriform, on short pedicels from a basal placenta. A genus of which about twenty species have been described, which inhabit principally the warmer parts of the world, some being widely diffused. They are as a whole difficult to distinguish, the specific marks being principally the ramification and shape of the branchlets, points in which the different species vary very much. The antheridia are very peculiar. On the upper branches are borne flattened, more or less incurved, disk-shaped branches, whose margin is wavy. The antheridia cover both sides of these discoidal branches, except at the margin, which is composed of large hyaline cells. The fronds are intermediate between those of Rhodomela and Laurencia, and the branchlets are always much constricted at the base. Most of the species were formerly included by Lamouroux and others in the genus Laurencia. By C. A. Agardh they were, in the Species Algarum, placed in Chondria, a genus retained by Harvey in the Nereis. Since as originally defined the genus Chondria embraced algæ of rather remote relationship to one another, J. G. Agardh, in the third volume of his Species Algarum, separated the present group, under the name of Chondriopsis, the name Chondria being
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:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
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: REPORT OF THE COMMISSIONER OF FISH
Page 163: REPORT OF THE COMMISSIONER OF FISH
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?