Art. XXVIII.—Notes on New Zealand Mosses: Genus Pottia.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 26, 1893, Page 288

Art. XXVIII.—Notes on New Zealand Mosses: Genus Pottia. By R. Brown. [Read before the Philosophical Institute of Canterbury, 1st November, 1893.] Plates XXXI.-XXXIV. The species composing this genus may be readily distinguished from those comprised in Gymnostomum, as the former are either annual or biennial plants, and the leaves have large cellular tissue. The members of this genus appear to have been entirely overlooked by botanists, as witness the Rev. J. Berkeley, who, in his introduction to “Cryptogamic Botany,” actually says, “This genus does not occur in New Zealand.” This may possibly be accounted for by the minuteness of the plants, also by the short time it takes them to arrive at maturity. They are to be found growing on steep damp clayey banks, where the earth during the hot summer months crumbles away, leaving a fresh surface for the spores of those plants to germinate on during the following winter; as their vigorous growth takes place only on freshly-turned soil, too much organic matter in the soil does not suit them. They speedily become extinct in those habitats; when this takes place a higher class of vegetation follows; they therefore form a section of the pioneers of vegetable life.

Campylopus bicolor, Hrnschuch.

Campylopus kirkii, Mitten

Dicnemon obsoletinerve

Macromitrium reusum H.F. & W.

Anisothecium gracillimim. sp. nov.

The best time for their successful collection is in wet or very damp weather, for on other days their leaves are generally curled up and appear dead, and then it is with great difficulty that they are discovered. The first record of any species belonging to this genus having been discovered in New Zealand which I have been able to find is that one described by Mr. Charles Knight as Gymnostomum areolatum in vol. vii., Trans. N.Z. Inst. p. 355. In another paper I have pointed out the anomalous position this particular moss (G. areolatum) holds, and proposed to place it in the genus Pottia, as being more in harmony with its character. The only other species which is said to belong to the genus Pottia is one described by Mr. T. W. Naylor Beckett in a paper contributed to the Philosophical Institute of Canterbury on the 5th October, 1892, and recorded in vol. xxv., p. 290, of the Trans. N.Z. Inst., and there named by him P. marginata. This plant has no actual existence, being a combination of a new species previously described by me in a paper read before the Philosophical Institute on the 7th September, 1892, and recorded in vol. xxv. of the Transactions, p. 286, and there named Hennedia microphylla, and a new species of this genus Pottia. The points of resemblance between these two species are many, both being found in the same situations, growing together in the same patches, having very similar leaves, and bordered margins. Here, however, the resemblance ends; H. microphylla having a simple stem, a mitriform calyptra covering the whole capsule tightly, and narrowed at the base; the Pottia having a cucullate calyptra, and only covering about one-half of the capsule. The cell tissue of the former is at least double the size of the latter. The capsule of the former has a straight, short, stout, conic operculum, while that of the latter has a long oblique one. It is unfortunate that Mr. Beckett has confounded these two species, as it necessitated his formulating a new development theory to explain his description of this moss. He knew that I had previously described this moss with the mitriform calyptra as H. microphylla, and, as he has attempted to give this moss a new generic and specific name, and has omitted to make any reference to H. microphylla, I am very reluctantly compelled, in order to prevent any confusion, to put this matter straight. I should like to have called the new species of Pottia, which he has confounded with Hennedia microphylla, Pottia marginata, in Mr. Beckett's honour; but, as under the cir-

cumstances this name would be quite inappropriate, I have named it Pottia grata. According to my usual practice, my drawings of the mosses described below are to one scale, to facilitate comparison. In this genus it will be found specially valuable on account of their minuteness. I have drawings of a few more plants which belong to this genus, but as I have mislaid my specimens I think it unwise to publish them until I have been able to compare further. The following arrangement of the species places them in their nearest relative position to each other:— Pottia areolata, Knight. " acaulis, nov. sp. " alfredii, nov. sp. " wrightii, nov. sp. " stevensii, nov. sp. " serrata, nov. sp. " longifolia, nov. sp. " bickertonii, nov. sp. " macrocarpa, nov. sp. " douglasii, nov. sp. " leonardi, nov. sp. " grata, nov. sp. " assimilis, nov. sp. " obliqua, nov. sp. Pottia acaulis, nov. sp. Plate XXXI. Plants minute, annual, almost stemless, simple, growing in small patches, gregarious. Leaves few, spreading. Upper stem-leaf 1/32in. long, oblong, rounded at the apex into a short acuminate point, concave. Margins entire. Nerve nearly continuous. Areola large; upper pentangular; lower oblong-quadrate, crisp when dry. Perichætial leaves 1/32in. long, oblong-obovate or subspathulate, rounded into an acute point. Fruitstalk 3/32in. Capsule small, ovate, symmetrical. Peristome none. Operculum conico-rostrate, slightly oblique, about two-thirds of the length of the capsule. Calyptra cucullate. Hab. On limestone rocks, at Castle Hill; and on Port Lyttelton Hills, on clayey banks. Collected by R. B. Pottia alfredii, nov. sp. Plate XXXI. Plants small, annual, growing in dense patches. Stem about ⅛in. long, unbranched. Leaves densely imbricating, numerous; upper nearly erect, lower spreading, shortly oblong-lanceolate, acute or apiculate, incurved near the apex, concave. Margins entire, recurved to near the apex. Nerve stout, excurrent, or ending at the apex. Upper areola slightly

dense, pentagonal; lower oblong-quadrate. Perichætial leaves slightly shorter, scarcely recurved on the margin, otherwise similar to the stem ones. Fruitstalk inclined, terminal, 3/32in. long. Capsule ovate. Peristome none. Operculum and calyptra not found. Hab. On damp banks, Port Lyttelton Hills. Collected by R. B. Pottia wrightii, nov. sp. Plate XXXI. Plants small, annual, growing in small patches, gregarious. Stems simple, about 1/32in. long. Leaves few, erecto-patent, oblong-lanceolate, acuminate, slightly incurved at the apex, concave. Margins entire. Nerve disappearing at the apex, Areola, upper pentangular, lower oblong-quadrate, crisp when dry. Perichætial leaves nearly erect, slightly narrower than the upper-stem ones, otherwise similar. Fruitstalk terminal, inclined, about ⅛in. long. Capsule oval, symmetrical, mouth small. Peristome none. Operculum slender, slightly oblique, about half the length of the capsule. Calyptra cucullate. Hab. On damp banks, Lyttelton Hills. Collected by R. B. Pottia stevensii, nov. sp. Plate XXXI. Plants minute, annual, growing in small loose gregarious patches. Stem extremely short. Leaves few, erecto-patent, broadly oblong-lanceolate, apiculate, slightly incurved near the apex, concave, margins entire. Nerve excurrent, lower leaves smaller, but otherwise similar to the upper. Areola small, upper pentagonal, lower oblong-quadrate, crisp when dry. Perichætial leaves smaller, the innermost one smallest, oblong-lanceolate, apiculate. Fruitstalk terminal, inclined, 3/16in. long, slender. Capsule ovate, symmetrical. Peristome none. Operculum oblique, conico-rostrate, two-thirds of the length of the capsule. Calyptra cucullate. Hab. Damp ground, in the Public Domain, Christchurch; not common. Collected by R. B. Pottia serrata, nov. sp. Plate XXXII. Plants small, growing in loose patches, gregarious. Stem simple or branched. Leaves, upper stem erecto-patent, oblong-lanceolate, acute or apiculate; lower small oblong-lanceolate, acute, slightly incurved near the apex, concave. Margins serrated towards the apex. Nerve excurrent. Areola, upper pentangular, lower oblong-quadrate, crisp when dry. Perichætial leaves, outer oblong-lanceolate, apiculate, serrated near the apex; inner smaller than the outer. Fruitstalk terminal, about ⅛in. long. Capsule ovate, symmetrical.

Peristome none. Operculum oblique, convexo - rostrate. Calyptra cucullate. Hab. On damp banks, Port Lyttelton Hills. Collected by R. B. Pottia longifolia, nov. sp. Plate XXXII. Plants small, pale-green, annual, growing in loose patches, gregarious. Stem simple or branched, about 1/32in. long. Leaves few, erecto-patent, upper large, oblong-lanceolate, acute; lower small, oblong-lanceolate, acute, very concave. Margins entire. Nerve ending at the apex. Areola, upper pentangular, lower oblong-quadrate, crisp when dry. Perichætial leaves smaller than the upper - stem ones, oblong-lanceolate, acute, otherwise similar. Fruitstalk terminal, about ⅛in. long, erect. Capsule ovate, symmetrical, mouth small. Peristome none. Calyptra cucullate. Hab. On damp clay-banks, at the head of Governor's Bay; July, 1882. Collected by R. B. Pottia bickertonii, nov. sp. Plate XXXII. Plants small, annual, yellowish-green, growing in patches, gregarious. Stem simple, about 1/32in. Leaves few, erecto-patent, lower linear-lanceolate, acute, middle oblong-lanceolate, acute; upper broadly oblong-lanceolate, acute, crisp when dry. Areola, upper pentagonal, lower oblong-quadrate. Perichætial shorter than the upper leaves, broadly ovate-lanceolate, acute, semiconvolute. Fruitstalk terminal, inclined, ⅛in. long. Capsule oval, symmetrical. Peristome none. Operculum slender, oblique, convexo-rostrate. Calyptra cucullate. Hab. Port Lyttelton hills, on damp banks. Collected by R. B. (Named in honour of Professor Bickerton, of Canterbury College, Christchurch.) Pottia macrocarpa, nov. sp. Plate XXXIII. Plants annual, growing in dense patches, gregarious. Stem simple, about ⅛in. long. Leaves numerous, closely imbricating; upper oblong-lanceolate, apiculate, or oblong rounded at the apex, apiculate, concave. Margins entire. Nerve excurrent. Lower stem-leaves smaller, but otherwise similar to upper ones. Areola, upper pentagonal, lower oblong-quadrate, crisp when dry. Perichætial leaves slightly shorter, otherwise similar to the stem ones. Fruitstalk terminal, nearly erect, 3/32in. long. Capsule large, ovate, subsymmetrical. Peristome none. Operculum stout, conico-rostrate, slightly oblique, nearly half the length of the capsule. Calyptra cucullate. Hab. Damp clay-banks, Port Lyttelton hills. Collected by R. B.

Pottia douglasii, nov. sp. Plate XXXIV. Plants dark-green, perennial. Stem short, ⅛in., branched. Branches short, ⅛in. Leaves erecto-patent, ovate-lanceolate, acuminate. Nerve excurrent. Margin minutely toothed near the apex by the excurrent cells. AreolEaE lax, quadrate below, pentangular towards the apex. Perichætial leaves longer, otherwise similar, incurved when dry. Fruitstalk nearly erect, ⅜in. to ½in., red, twisted to the right when dry. Capsule obconic or turbinate, red. Operculum oblique, conicosubulate. Columella adherent to the operculum, and falling away with it. Calyptra cucullate. Hab. Hagley Park, on marshy ground, growing along with Physcomitrium pyriforme; in fruit November, 1878; found by myself then, and afterwards by T. G. Wright in the same locality. This habitat has since been destroyed through the place having been drained, and now used as a racing-track. I have not been able to find this moss in any other locality. A specimen plant was deposited by me in the Museum, 1885. Pottia leonardi, nov. sp. Plate XXXIII. Plants very small, annual, pale-green, growing in small loose patches. Stem about 1/32in., simple. Leaves few, closely imbricating, erecto-patent. Upper lanceolate acute, narrowed towards the base, concave. Margin entire. Nerve continuous. Areola, upper pentagonal, lower oblong-quadrate, crisp when dry. Perichætial leaves slightly smaller than the stem ones, otherwise similar. Fruitstalk terminal, ⅛in. long, inclined. Capsule ovate, symmetrical. Peristome none. Operculum oblique, conico-rostrate, stout or slender, two-thirds the length of the capsule. Calyptra cucullate. Hab. Damp clay-banks, Port Lyttelton hills; August, 1892. Collected by R. B. Pottia grata, nov. sp. Plate XXXIII. Plants small, pale-green, annual, growing in patches, gregarious. Stem most minute, simple or branched from near the base. Branch fastigiate. Leaves imbricating, erecto-patent, oblong-lanceolate acute or ovate-lanceolate acute, concave. Margin having a border of quadrate pellucid cells, and serrated near the apex, crisp when dry. Areola, upper small, pentagonal, lower oblong-quadrate. Perichætial leaves ovate-lanceolate, acute. Margin bordered with quadrate cells, serrated near apex. Nerve continuous. Fruitstalk terminal, inclined, ⅛in. long. Capsule elliptic. Peristome none. Operculum stout, oblique, conic, about half the length of the capsule. Calyptra cucullate, covering about half the capsule.

Hab. Damp banks, neighbourhood of Christchurch. Collected by R. B. (Note.—This is the plant which Mr. Beckett has confounded with H. microphylla.) Pottia assimilis nov. sp. Plate XXXIV. Plants small, annual, dark-green, growing in dense patches. Stem 1/16in. long, branched near the base. Branches fastigiate. Leaves many, densely imbricating, erecto-patent, oblong-lanceolate, acute, crisp when dry; upper broadly oblong-lanceolate, acute, concave. Margin entire. Nerve ceasing at the apex. Areola, upper pentangular, lower oblong-quadrate. Perichætial leaves short, otherwise similar to those of the stem. Fruitstalk terminal, 3/32in. long, inclined. Capsule obliquely ovate, unsymmetrical, mouth narrow. Peristome none. Operculum oblique, conico-rostrate, half the length of the capsule. Calyptra cucullate. Hab. On damp banks, Merivale, near Christchurch. Collected by R. B. Pottia obliqua, nov. sp. Plate XXXIV. Plants very small, annual, pale-green, growing in loose patches, gregarious. Stem extremely short, simple or branched close to the base. Leaves few, spreading, or erectopatent, incurving near the apex, oblong-lanceolate, acuminate, slightly narrowed towards the base, concave. Margins entire, nerved towards the apex, crisp when dry. Areola, upper pentagonal, lower oblong-quadrate. Perichætial leaves oblong-lanceolate, acuminate. Fruitstalk terminal, pale, inclined obliquely, ⅛in. long. Capsule ovate, nearly symmetrical. Peristome none. Operculum conico-rostrate, half the length of the capsule. Calyptra cucullate. Hab. On damp ground, Port Lyttelton Hills. Collected by R. B. Explanation of Plates XXXI.-XXXIV. Plate XXXI. Pottia acaulis. Fig. Pottia alfredii. 1. Upper portion of plant, with capsule and perichætial leaves. 2. Upper stem leaf. Pottia wrightii. 1. Capsule and operculum. 2. Perichætial leaf (inner). 3. Perichætial leaf (outer). 4. Stem leaf (upper). 5. Stem leaf (middle). 6. Stem leaf (lower).

Pottia stevensii. 1. Capsule and operculum. 2. Perichætial leaf (inner). 3. Perichætial leaf (outer). 4. Stem leaves (upper). Plate XXXII. Fig. Pottia serrata. 1. Capsule and operculum. 2. Perichætial leaf (inner). 3. Perichætial leaf (outer). 4. Stem leaves (upper). Pottia longifolia. 1. Capsule and operculum. 2. Calyptra. 3. Perichætial leaf (inner). 4. Stem leaf (upper). 5. Stem leaf (lower). Pottia bickertonii. 1. Capsule and operculum. 2. Perichætial leaf (inner). 3. Stem leaf (upper). 4. Stem leaf (middle). 5. Stem leaf (lower). Plate XXXIII. Fig. Pottia macrocarpa. 1. Capsule and operculum. 2. Perichætial leaf (inner). 3. Stem leaf (upper). 4. Stem leaf (middle). 5. Stem leaf (lower). Pottia leonardi. 1. Capsule and operculum. 2. Calyptra. 3. Perichætial leaf (inner). 4. Perichætial leaf (outer). 5. Stem leaf (upper). Pottia grata. 1. Capsule and operculum. 2. Calyptra. 3. Perichætial leaf (inner). 4. Perichætial leaf (outer). 5. Stem leaf (upper). Plate XXXIV. Fig. Pottia assimilis. 1. Capsule and operculum. 2. Perichætial leaf (inner). 3. Perichætial leaf (outer). 4. Stem leaf (upper). 5. Stem leaves (middle).

Fig. Pottia obliqua. 1. Capsule and operculum. 2. Perichætial leaf (outer). 3. Perichætial leaf (inner). 4. Stem leaves (upper). Pottia douglasii. 1. Capsule and operculum. 2. Calyptra. 3. Perichætial leaf (inner). 4. Perichætial leaf (outer). 5. Stem leaf (upper).