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Tuatara: Volume 21, Issue 3, April 1975

Notes on the Liverwort Family Ricciaceae in New Zealand

page 121

Notes on the Liverwort Family Ricciaceae in New Zealand

Abstract

Riccia bifurca and R. crystallina are recorded for New Zealand.

Notes are given on R. fluitans and Ricciocarpos natans.

The liverwort family Ricciaceae is represented in New Zealand by two genera, Ricciocarpos and Riccia. The plants are small and grow either floating in water or as rosettes or irregular colonies on soil. Ricciaceae is distinguished from other families of the Marchantiales by the simple construction of the sporophyte and its immersion in the thallus. The sporophyte is a spherical capsule which contains spores and in some cases sterile cells, but not functional elaters. It has no seta or foot.

A key to the two genera is as follows:
1.Plants usually floating on water, rarely growing on damp soil; thallus composed of thin plates of cells enclosing large air cavities; ventral scales in 3-5 series on both sides of the mid-line or lacking … Ricciocarpos
2.Plants growing on soil (except the floating form of R. fluitans); thallus consisting of an upper layer, where air cavities are bounded by walls of green cells or by columns of green cells, and a lower layer made of ground tissue; ventral scales in one or two series (in total) or lacking … Riccia
Since plants of Riccia are often ephemeral, it is likely that other species apart from those mentioned in this paper will be found in New Zealand. In fact, some are already known to be present but have not been obtained in quantities sufficient for determination.

The Genus Ricciocarpos

Ricciocarpos natans (L.) Corda

Description of the Plant

Plants are found as spongy rosettes or partial rosettes, up to 20 mm in diameter, either floating on ponds or stranded at the margin. Individual branches are up to 10 mm long and 8 mm wide.

The floating form is little branched and of a green or yellow-green colour (Fig. 1). The upper surface is firm and convex with a deep median furrow. On the under surface are few, if any, rhizoids but there are numerous conspicuous and characteristic, pendant scales. These are toothed, ribbon-shaped, and reddish-violet or brownish-green in colour. They have long-continued growth from a basal meristem. Branching is by forking of the apex and occasionally by adventitious ventral shoots. page 122
Fig. 1: Thallus of Ricciocarpos natans showing projecting scales.

Fig. 1: Thallus of Ricciocarpos natans showing projecting scales.

Fig. 2: Scanning electronmicrograph of Ricciocarpos natans showing pores in the upper surface of the thallus.

Fig. 2: Scanning electronmicrograph of Ricciocarpos natans showing pores in the upper surface of the thallus.

The stranded form is of temporary occurrence in New Zealand as, unless protected, it is soon killed by exposure to wind and the heat of the summer sun. It differs in being more freely branched, in having numerous smooth and tuberculate rhizoids, but only rudimentary scales.

R. natans is reported to be monoicous. Sexual reproduction is reported to occur only in floating plants (Garber, 1904). None of the New Zealand plants which were examined were fertile.

Anatomy of the Thallus

The thallus is up to 3 mm deep. The upper epidermis is interrupted by simple air-pores (Fig. 2). The rest of the thallus is composed of several series of large air chambers bounded by unistratose walls (Fig.10). Cells in the upper part have chloroplasts, below they are colourless. Marginal and ventral cells may have reddish-violet walls.

Distribution

R. natans is cosmopolitan (Hassel de Menendez, 1962). Since it was collected by Colenso (Hooker, 1855) it is considered to be indigenous. Specimens were examined from lakes in the North Island, Marlborough and Canterbury.

The Genus Riccia

This large genus is divided into two subgenera, namely (1) Riccia with a rather compact photosynthetic layer consisting of more or less vertical filaments separating narrow air chambers and (2) Ricciella with a spongy photosynthetic layer consisting of unistratose walls enclosing large, polydedral air chambers. page 123
Fig. 3: Thallus of Riccia bifurca.

Fig. 3: Thallus of Riccia bifurca.

Subgenus Riccia
Riccia bifurca Hoffm.

Description of the Plant

The plants are found on soil, usually as extensive irregular colonies, but occasionally as rosettes up to 1 cm in diameter (Fig. 3). Branches are up to 4 mm long and 1-2 mm wide. The thallus is firm, green or glaucous-green in colour, and has a flat surface except at the deeply-grooved mid-line. This latter is characteristic in being narrow near the apex, then widening to as much as one-third the thallus width, and still further back becoming indistinct. The upper surface, when viewed at a magnification of X 10 or higher, appears marked out into squares, the boundaries of which represent the lateral walls of the epidermal cells (Fig. 4). On the under surface are smooth rhizoids of diameter 17-25 μm, tuberculate rhizoids of diameter 10-12.5 μm, and small, hyaline scales which extend almost to the margin but wither early. Branching is by forking at the apex and by ventral adventitious shoots. Plants are monoicous. The black, tetrahedral spores have triradiate and reticulate markings and papillate projections (Fig. 5). There are conspicuous germ-pores and a broad wing. page 124
Fig. 4: Scanning electronmicrograph of part of the upper surface of Riccia bifurca after freeze-drying.

Fig. 4: Scanning electronmicrograph of part of the upper surface of Riccia bifurca after freeze-drying.

Fig. 5: Scanning electronmicrograph of spores of Riccia bifurca.

Fig. 5: Scanning electronmicrograph of spores of Riccia bifurca.

Anatomy of the Thallus

The thallus in transverse section is 0.7 mm deep (Fig. 11). The dorsal epidermis consists of 1-2 layers of cells. Near the apex the free walls project in rounded or mammillate form but later collapse, leaving the firm lateral walls in position. The photosynthetic tissue consists above of vertical columns of cells, 0.2-0.5 mm high, separated by narrow vertical air chambers and gradually merges into a compact, ventral tissue with fewer chloroplasts.

Distribution

R. bifurca is known from Europe, North America (Frye and Clark, 1937) and from Australia (R. D. Seppelt pers. comm.). Probably it has been introduced into New Zealand. It has been collected from garden soil at Avenue Nurseries, Levin (E. O. Campbell 17/7/73 MPN 17011).

Subgenus Ricciella
1. Riccia crystallina L. emend. Raddi

Description of the Plant

The plants are found on soil, usually as spongy rosettes, up to 3 cm in diameter and occasionally as irregular colonies of larger size (Fig. 6). Branches are up to 4 mm long and 1-2 mm broad. The colour of young plants is glassy green, of older plants grey-green. The upper surface at first is smooth but tends to collapse and erode with age. It is normally flat or slightly convex but in young parts may show a shallow groove at the mid-line. The under surface page 125
Fig. 6: Thallus of Riccia crystallina.

Fig. 6: Thallus of Riccia crystallina.

Fig. 7: Scanning electronmicrographs of a spore of Riccia crystallina: (a) distal face; (b) proximal face showing triradiate marking.

Fig. 7: Scanning electronmicrographs of a spore of Riccia crystallina: (a) distal face; (b) proximal face showing triradiate marking.

carries smooth rhizoids of diameter 25 μm and tuberculate rhizoids of diameter 15-20 μm but lacks scales. Branching takes place by forking at the apex and in older thalli under humid conditions by marginal or ventral adventitious shoots. page 126
Fig. 8: Thallus of stranded form of Riccia fluitans.

Fig. 8: Thallus of stranded form of Riccia fluitans.

Fig. 9: Scanning electronmicrographs of a spore of Riccia fluitans: (a) distal face; (b) part of same at a higher magnification.

Fig. 9: Scanning electronmicrographs of a spore of Riccia fluitans: (a) distal face; (b) part of same at a higher magnification.

The species is monoicous. The dark brown tetrahedral spores have a conspicuous triradiate and incomplete reticulate markings. There is a broad wing with a crenate margin (Fig. 7). Cytology, spore morphology and spore germination have been described previously (Chopra and Udar, 1957; Jovet-Ast, 1964-5, 1966; Seppelt, 1974; Udar, 1957).

Anatomy of the Thallus

The thallus shows differentiation into epidermis, photosynthetic tissue and compact ventral tissue (Fig. 13). In transverse section it is 0.5 mm deep. The dorsal epidermis consists of colourless, subspherical or papilliform cells which readily collapse. Beneath this page 127
Fig. 10: Transverse section of part of the thallus of Ricciocarpos natans.

Fig. 10: Transverse section of part of the thallus of Ricciocarpos natans.

Fig. 11: Transverse section of part of the thallus of Riccia bifurca.

Fig. 11: Transverse section of part of the thallus of Riccia bifurca.

Fig. 12: Transverse section of part of the thallus of Riccia fluitans. Fig. 13: Transverse section of part of the thallus of Riccia crystallina.

Fig. 12: Transverse section of part of the thallus of Riccia fluitans.
Fig. 13: Transverse section of part of the thallus of Riccia crystallina.

epidermis is spongy photosynthetic tissue consisting of delicate unistratose partitions separating 2 to 4 layers of large air spaces. The compact ventral tissue has a depth of 3 to 5 thin-walled, almost colourless cells, decreasing to one at the margin.

Distribution

R. crystallina is cosmopolitan (Hassel de Menendez, 1962; R. D. Seppelt pers, comm.). Probably it has been introduced to New Zealand for it occurs on garden soil, usually as a spring ephemeral. It has been collected from the following localities in New Zealand: Grounds of Massey University, Palmerston North (E. O. Campbell page 128 24/10/73 MPN 17005); garden at 70 Kelburn Road, Wellington (M. J. Parsons 20/9/60 MPN 17008); N.Z. Forest Service Nursery, Bulls (E. O. Campbell 16/10/73 MPN 17009); Esplanade, Palmerston North (Zotov 3/10/33 CHR 7011. E. O. Campbell 24/10/73 MPN 17006); garden of J. Foweraker, Christchurch, where it has been known since 1928 (E. O. Campbell 5/10/73 MPN 17007); summit of Mt. Eden, Auckland (E. O. Campbell 18/8/74 MPN 17017).

2. Riccia fluitans L.

Description of the Plant

There are two forms of R. fluitans, one found floating or suspended in lakes, the other stranded in shallow or temporary pools. The floating form has a ribbon-shaped, green thallus, up to 9 cm long, forking at intervals of 0.8-10 mm. Branches are up to 0.3 mm in width. The upper surface is flat except for a shallow median groove near the apex. At a magnification of X 10 or higher it has a coarsely reticulate appearance produced by partitions between large air cavities in the thallus. Rhizoids and scales are lacking.

Plants of the stranded form are green or reddish-purple in colour. As compared with the floating form they branch more frequently (at intervals of 0.8-4 mm) and the branches tend to be wider (up to 0.6 mm) (Fig. 8). On the under side are smooth rhizoids of diameter 13-23 μm, tuberculate rhizoids of diameter 13-26 μm and sometimes residual fragments of scales. The species is monoicous. In New Zealand sporangia are readily produced on stranded plants. The spores have a broad wing and show reticulate markings (Fig. 9).

Anatomy of the Thallus

The thallus is up to 0.16 mm deep (Fig. 12). The epidermis is persistent, unistratose and in stranded forms is interrupted by minute pores. Most of the thallus is a spongy, photosynthetic tissue composed of unistratose partitions separating large air cavities, but on the lower surface, particularly in the stranded form, is a compact tissue 2-3 cells deep.

Distribution

R. fluitans is cosmopolitan (Stephani, 1898-1924). As it was collected in New Zealand by Colenso (Hooker, 1855), it is considered to be indigenous. Specimens studied were from Lake Rotoma, Rotorua (P. Sarma 14/5/73 MPN 17010); Fish Hatcheries, Masterton (C. T. Moss 9/46 CHR 163417); and Waituna Lagoon, Southland (L. B. Moore 6/1/69 CHR 161583).

Acknowledgements

The writer is indebted to R. D. Seppelt for identifying specimens of R. bifurca and R. crystallina; to K. Card, D.S.I.R. Physics and Engineering Laboratory, for the scanning electron micrographs; and to Botany Division, D.S.I.R., for the loan of herbarium specimens.

page 129

References

Chopra, N., and Udar, R., 1957: Cyto-taxonomic studies in the genus Riccia (Mich.) L. Journal of the Indian Botanical Society 4: 535-538.

Frye, T. C., and Clark, L., 1937: Hepaticae of North America. University of Washington Publications in Biology 6 (1): 15-16.

Garber, J. F., 1904: The life history of Ricciocarpos natans. Botanical Gazette 37: 161-177.

Hassel de Menendez, G. G., 1962: Estudio de las Anthocerotales y Marchantiales de la Argentina. Opera Lilloana 7: 1-297.

Hooker, J. D., 1855: Flora novae-zelandiae. Vol. 2 in Antarctic Voyage of H.M. Discovery Ships Erebus and Terror. Lovell Reeve. London.

Jovet-Ast, S., 1964-5: Riccia crystallina L. emend. Raddi et Riccia cavernosa Hoffm, emend. Raddi (Note preliminaire). Revue bryologique et lichenologique 33: 459-483.

——, 1966: Riccia crystallina L. emend. Raddi et Riccia cavernosa Hoffm, emend. Raddi II. Revue bryologique et lichenologique 34: 82-90.

Seppelt, R. D., 1974: Riccia crystallina in South Australia. The Bryologist 77: 224-229.

Stephani, F., 1898-1924: Species hepaticarum. Vols. 1-6. Geneva.

Udar, R., 1957: Culture studies in the genus Riccia (Mich.) L. Journal of the Indian Botanical Society 4: 580-586.

Painted Lady Butterfly

Until recently I had never seen the Painted Lady Butterfly (Vanessa kershawi) in some forty years of insect-watching, though this may conceivably be a measure of my poor powers of observation rather than to the insect's rarity in New Zealand. However, I sighted one on December 15, 1973, in the grounds of Hereworth School, Havelock North, and another on January 18, 1974, on the property of Mr Thomas Crosse at Patoka in northern Hawke's Bay. The Painted Lady is usually assumed to be a visitor from Australia as it has never yet been caught in the act of breeding here, though there is general agreement that there is no particular reason why it should not as its food plants (various species of thistle) are available in this country. The Patoka specimen was certainly battered and shabby and looked as if it could easily have come from Australia, or the world's end for that matter. However, the Havelock North specimen, which alighted on a flower a few feet from me, seemed to be undamaged and fresh and in what stamp collectors would describe as mint condition. It was extremely difficult to believe that it had arrived from Australia, particularly as Hawke's Bay is on the east side of the island and there had been no prolonged periods of strong westerlies for some time before that.

It would be interesting to hear of any other observations of these butterflies that readers have made.