This genus is described from a single specimen in the British Museum, collected by Mr. Menzies; it has evidently been torn by the waves on the edges, and is not in such a good state as one might wish. There are three, or rather the parts of three, oblong fronds, a smaller one from each side of the base of the larger, each of the three supported by a thin articulated filament, arising from an elongated stem an inch or so in length, with opposite branches.

As fixed on the paper with gum, the three fronds seem to coalesce at the edge, where they touch or overlap, but this may be only from the manner in which the specimen is mounted, and I fear that if it were attempted to be re-spread, the specimen might be injured, so we must wait until more specimens are obtained to settle the form of the edges of the frond and other particulars relating to it.

There can be no doubt that its habit is very different from that of the species of the genus Microdictyon, and that it is a beautiful Alga. I can hardly understand how it has remained so long undescribed, but I cannot find any reference to it in any work within my reach. 1. Phyllodictyon pulcherrimum.

HAB. Gulf of Mexico, Archibald Menzies, Esq., 1802, Herb. Brit. Mus. The fronds are ten inches long and about three inches wide.

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The Cladophora (?) anastomosans, Harvey, Phycologia Australica,' t. 101, is nearly allied to this genus. It must form a genus to which the name of Pterodictyon may be applied. It differs from Phyllodictyon, in which all the joints of the oblong frond are of nearly the same length, in the broad triangular shape of the frond, produced by the different length of the joints of the stipes and of the main branches. These joints gradually and regularly diminish in length as they approach the margin of the frond, "the former is stipitate, dichotomously bi-tripinnate, the pinnæ and pinnulæ opposite and horizontally patent, the alternate pinnules here and there anastomosing," and "arising from a wall of irregular branched filaments." Dr. Harvey believes the single specimen described and figured, which was cast ashore near Fremantle, Swan River, to be the young state of a species that is more netted in its adult age; the form of the frond and the length of the basal joint cannot be altered in the growth, and therefore Pterodictyon anastomosans must always be easily distinguished from Phyllodictyon.

Dr. Harvey mentions Cladophora composita; this is a section of the

"

genus, or a species, that has neither occurred to me in any work no herbarium.

ADDITIONAL NOTES ON ANADYOMENE.

Since the printing of the first portion of this paper, Dr. Harvey has kindly sent me some notes on it, and some additional specimens for my collation and for examination.

His specimen of Grayemma Menziesii is much smaller than the one in the British Museum, and a considerable number of the filaments are formed of a single series of cells, but all these simple lines of single cells are continued for the length of several cells, without giving out any branches; they terminate in three or four equal cells, which are continued side by side according to what I consider the normal structure of the plant, or, after one or two such groups of cells, they split off again into long threads, formed of a single series of long linear cells, one on the end of the other. These varieties confirm me in the distinctness of the plant as a genus for the Anadyomene.

Dr. Harvey has also sent me some specimens of an Anadyomene from West Florida and from Bermuda, which certainly show that this species is variable in the size and form of the cells; and there is one specimen which seems in his opinion to combine the two species. He says the soft rigid state of the frond depends partly on the age of the specimen, partly on the length of time it is steeped in fresh water, and partly on the manner of drying. "The Key West plants, which are as common as Ulva are here, also differ greatly in the length of the joints of the generating filaments in different parts of the plant."

Amongst the specimens which Dr. Harvey has so kindly sent me is one named "Anadyomene (?) Leclancheri, Decaisne," from the Sooloo Archipelago. This plant shows that the characters which I have given to the tribe must be modified, and that the genera should be arranged into two groups, the first containing the genera I have described; they have the interspaces between the generating filaments filled up with smaller cells, making a continuous frond. The second has part of the interspaces between the filaments void, forming a netted frond, pierced with roundish holes or spaces between the meshes.

The Algae of this group, though it has the netted frond, as in Microdictyon, cannot be confounded with that genus, as the mesh is formed of many different-sized and very variously-disposed cells, some

of them radiating from a centre, while in Microdictyon each side of the mesh is formed of a single conferva-like cell.

On this account I propose to call the genus Cystodictyon.

CYSTODICTYON.

The frond netted with rounded holes or spaces between the meshes, formed of elongate subcylindrical joints, giving out at certain distances a radiating fan-like series of cells, the interspaces between the longitudinal filament and the fan-like cells being filled up with unequal small cells.

Cystodictyon Leclancherii, t. f.-Anadyomene (?) Leclancherii, De

caisne.

HAB. Sooloo Archipelago, Herb. Harvey and Gray.

EXPLANATION OF PLATE XLIV.

Fig. 1. Grayemma Menziesii, nat. size; 2, magnified section of ditto; 3, magnified section of Calomena Brownii; 4, magnified section of Anadyomene Cutleria; 5, magnified section of Anadyomene Wrightii; 6, magnified section of Cystodictyon Leclancherii.

THIRSK BOTANICAL EXCHANGE CLUB.

(CURATOR'S REPORT FOR 1865.)

BY J. G. BAKER, ESQ., AND WILLIAM FOGGITT, ESQ.

As in previous years, we propose to give here a brief notice of the more interesting plants that have come before us during the past year, restricting such notice, as will be seen, to plants of which specimens have passed through our hands, notable either on the score of critical interest, or as having been found in tracts whence they are not registered in the Cybele Britannica' and its Supplement.

Thalictrum flexuosum, var. Through the kindness of Mr. William Richardson in sending a bundle of roots and living specimens of the Thalictrum of the exposed basaltic crags of Kyloe, near Belford, Northumberland, we are enabled to furnish the following description: -Stem 1 foot to 18 inches in height, green or purplish, leafy to the base, zigzag, hollow in the centre, not compressible, subterete, hardly striated towards the base, but marked in the upper part, especially below the sheaths, slightly glandular. Lower stipules with adpressed, upper with reflexed auricles. Leaves bipinnate; the leaflets pale green

above, glaucous and covered beneath with shining sessile glands, the terminal segment about 1⁄2 inch broad and deep, cuneate or rounded or even cordate at the base, three-parted at the apex, and sometimes the partings again toothed. Main petiole rounded, and marked with three striations on the back, channelled above, both the main and secondary petioles spreading from the axis at right angles. Panicle very diffuse, half the whole length of the stem or nearly so, the general outline broadly triangular, the lowest branch only furnished with a leafy bract about half its length; the branches patent or erecto-patent, arcuate, only 9 to 12 distant flowers upon the main branches. Anthers apiculate, 1 line long, pendent; the pedicel 2 lines long. Sepals narrowly ovate, 2 lines long. Carpels 2 lines long without the style, narrowly ovate, rather gibbous, irregularly 10-nerved, some of the nerves faint, and others deeper. From the ordinary north of England riverside form of the plant this differs principally by its hollow stem, smaller glandular glaucous leaflets, and few-flowered leafy panicle.

Viola permixta, Jordan. M. Jordan identifies the Viola gathered by Mr. Briggs, near Plymouth, and described in our report of last year as intermediate between hirta and odorata, with his own V. permixta (fasc. 7, p. 6, Boreau Fl. du Centre, 3rd edit. vol. ii. p. 74). He sends examples of this gathered in the neighbourhood of Lyons, and the comparison of our plant with these and an authenticated specimen sent by Professor Van Heurck, from Antwerp, leaves little room to doubt their substantial identity, though there are one or two trifling points of discrepancy in the published descriptions. Mr. Briggs took the trouble to send in spring several living examples of the Devonshire plant, and we give now a more complete description of it, side by side. with one of the ordinary V. odorata.

V. permixta.

Rootstock woody, scaly, wide-creeping, sending out stolons, which bear tufts of leaves and flowers, and occasionally take root.

Petioles covered throughout with short stiff deflexed hairs at the flowering time, some of them 4 or 5 inches long, which is longer than the peduncles.

Leaves hairy all over on both sides,

I. odorata.

Rootstock woody, scaly, widecreeping, sending out long-rooting stolons, which bear tufts of leaves and flowers.

Petioles 1-2 inches long at the flowering time, some rather densely hairy with deflexed hairs, some nearly hairless, or the hairs so short as to be quite inconspicuous.

Leaves rather less hairy on both

measuring at the flowering time about 1 inch long, including the lobes, by 1 broad, expanding in autumn to 4 inches by 2, so much cordate that there is only a narrow sinus left between the lobes, which are inch deep.

Stipules lanceolate, the ciliations few and very short.

Peduncles weak, slender, 2-4 inches long when the plant is in flower, the lower part hairy, the upper with only a few scattered hairs; the bracts linear and slightly gland-ciliated, placed usually below the middle of the peduncle.

Sepals oblong, blunt, faintly ciliated along the lower third of the edge; petals slaty-blue, the upper pair imbricated, inch wide, the lateral pair rather narrower, the lowest one inch across, distinctly emarginate at the apex, narrowed more gradually than in the other, and with fewer veins; the spur inch from its extremity to the tip of the lower petal; the antherspur blunt, curved upwards, four to six times as long as broad.

Inodorous, or faintly scented.

Viola lutea, var. hamulata. Having now raised from seed the Pansy from Marrick Moor, near Richmond, mentioned in Baker's 'North Yorkshire,' as a form under lutea, and grown it for three years without finding it lose its characteristics, we give a description of it here, to draw the attention of botanists to it as a possibly distinct variety or sub-species, bearing in some respects the same relation to typical lutea that arvensis has to tricolor. Rootstock thread-like, perennial, widecreeping. Stems diffuse, much branched at the base, slender, quadrangular, pubescent below, but the pedicels naked. Lower leaves on naked channelled stalks about a of an inch long, roundish, with ciliated crenations about as broad as deep; upper ovate, bluntish, or even lanceolate, acute, with crenations two or three times as broad as deep. Stipules with the terminal lobe much larger than the others,