Manual of the New Zealand Flora.
Order XXVII. Halorageæ
Order XXVII. Halorageæ.
Herbs, often aquatic, rarely undershrubs. Leaves opposite, alternate, or whorled, when submerged often pectinately pinnatifid; stipules wanting. Flowers hermaphrodite or unisexual, always small and often incomplete. Calyx-tube adnate to the ovary; lobes 2, 4, or wanting. Petals 2, 4, or wanting, valvate or slightly imbricate. Stamens 2 or 4–8, rarely 1 or 3, large, epigynous; filaments short, filiform; anthers 2-celled. Ovary inferior, compressed, angled or ribbed, rarely 2–4-winged. 2- or 4-celled, rarely 3-celled; styles 1–4, distinct; stigmas papillose or plumose; ovules as many as the styles, pendulous, anatropous. Fruit small, dry or succulent, 1–4-celled, indehiscent or separating into 1–4 indehiscent carpels. Seeds solitary in the cells, pendulous; albumen fleshy, usually copious; embryo cylindrical, axile.
A small order of mostly inconspicuous plants, many of them water-weeds. Genera 8 or 9; species from 80 to 90. I have followed Hooker and Bentham in keeping Callitriche in this order, but it must be admitted that it has equal claims to be placed among the Monochlamydeœ. Of the 4 New Zealand genera, Haloragis is mainly Australian, but extends northwards as far as Japan; Myriophyllum and Callitriche are almost of world-wide occurrence; while Gunnera belongs to the south temperate zone.
Terrestrial. Calyx 4-lobed. Stamens 4–8. Petals valvate. Fruit nut-like, undivided 1. Haloragis. Aquatic. Calyx-lobes obscure. Stamens 4–8. Petals imbricate. Fruit separating into 2–4 nut-like carpels 2. Myriophtllum. Subaquatic or terrestrial. Stamens usually 2. Fruit a 1-seeded drupe 3. Gunnera. Aquatic or subaquatic. Stamen 1. Styles 2. Seeds 4 4. Callitriche.
1. Haloragis, Forst.
Erect or procumbent branching wiry herbs, sometimes almost woody at the base. Leaves opposite or alternate, entire or toothed or lobed. Flowers unisexual or hermaphrodite, minute, axillary, solitary or clustered, often spicate or racemose. Calyx-tube 4–8-angled or winged; lobes 4, erect, persistent. Petals 4, cucullate, acute, coriaceous, often wanting in the female flowers. Stamens 4–8, filaments usually short. Ovary 2–4-celled; ovules solitary in each cell, pendulous; styles short, stigmas usually plumose in the female flowers. Fruit a small dry 2–4-celled 2–4-seeded nut, sometimes 1-celled and 1-seeded by abortion; the adnate calyx-tube either smooth, ribbed, or muricate.
About 50 species are known, mostly from Australia, but a few are also found in New Caledonia, eastern Asia, and temperate South America (Juan Fernandez). Four of the New Zealand species occur in Australia, and one in the island of Juan Fernandez as well.
Leaves large, lanceolate or oblong, 1–3 in. Flowers crowded, drooping 1. H. alata. Leaves small, ¼–¾ in., floral ones alternate. Flowers erect, spicate. Fruit 4–8-costate, rugose or tuberculate between the ribs 2. H. tetragyna. Leaves small, 1/10–½ in., floral ones opposite. Flowers erect, spicate or solitary. Fruit 4–8-costate, smooth between the ribs 3. H. depressa. Leaves small, ⅓–⅔ in. Flowers in terminal panicles. Fruit 4–8-costate, smooth between the ribs. 4. H. spicata. Leaves small, ⅕–⅓ in. Flowers drooping, in naked spikes. Fruit 8-costate, smooth between the ribs. 5. H. micrantha.
2. Myriophyllum, Linn.
Glabrous marsh or aquatic herbs, branches often floating. Leaves opposite, alternate, or whorled, the lower leaves when submerged often pinnately divided with capillary segments. Flowers usually monœcious, axillary, solitary or spiked. Males: Calyx-tube very short; limb 4- or rarely 2-lobed or wanting. Petals 2–4,. concave. Stamens 2, 4, or 8. Females: Calyx - tube deeply 4-grooved; limb wanting, or of 4 minute subulate lobes. Petals minute or wanting. Ovary inferior, 4- or rarely 2-celled; styles 4 or 2, usually recurved or plumose; ovules solitary in each cell. Fruit deeply 4-furrowed, usually separating into 4 dry indehiscent. 1-seeded nuts.
A widely distributed genus of from 15 to 20 species, found in fresh waters in nearly all parts of the world. One of the New Zealand species is endemic, the rest extend to Australia, and one to South America as well.
Leaves whorled; lower pectinately pinnatifid, with capillary segments; upper oblong, entire 1. M. elatinoides. Leaves whorled; lower pectinately pinnatifid, with capillary segments; upper linear, entire or serrate 2. M. intermedium. Leaves whorled, all pectinately pinnatifid. Nuts large, tubercled 3. M. robustum. Minute, 1–3 in. All the leaves opposite, minute, linear-spathulate, entire 4. M. pedunculatum.
3. Gunnera, Linn.
Stemless herbs with creeping rhizomes, often forming broad matted patches. Leaves all radical, petiolate, ovate-or rounded-cordate, coriaceous and fleshy. Flowers small, unisexual or rarely hermaphrodite, in simple or branched spikes or panicles. Male flowers: Calyx-tube imperfect or wanting; lobes 2–3, minute. Petals 2–3 or wanting. Stamens 2–3; filaments filiform; anthers large. Females: Calyx-tube ovoid; lobes 2–3, small. Petals 2–3,. or wanting. Ovary 1-celled; styles 2, rarely 4, linear, papillose, stigmatic from the base; ovule solitary, pendulous. Fruit a small fleshy or coriaceous drupe; seed adherent to the pericarp; embryo very minute.
From 20 to 25 species are known, nearly half of them being endemic in New Zealand. The remainder are chiefly found in America, ranging from Mexico to Chili, Juan Fernandez, Fuegia, and the Falkland Islands. There are also outlying species in South Africa, Java, Tasmania, and the Sandwich Islands.
The New Zealand species of Gunnera are very imperfectly understood, and are much in need of a thorough revision, which should be based as far as possible upon a study of the various forms in a living state. The following account, although as complete as the material at my command will permit, is deficient in many respects, and I have been compelled to omit all notice of several doubtful plants from inability to refer them to their proper places until more complete specimens are obtained. The student should be careful to gather his flowering and fruiting specimens in the same locality, and if possible from the same patch, the similarity between the foliage of several of the species making it difficult to be sure that the specimens are properly matched unless this is done. It is also much to be desired that a regular series of specimens, both flowering and fruiting, should be taken at fixed intervals during the season, there being reason to suppose that both inflorescence and fruit exhibit differences at different periods of the year.
* Scapes bisexual; female flowers at the base. Leaves coriaceous, orbicular or reniform, crenate-dentate, often 3–5-lobed 1. G. monoica. Leaves rather thin, ovate or ovate-cordate 2. G. microcarpa. ** Scapes unisexual. Slender, 1–4 in. Leaves ovate or ovate-cordate. Fruiting scape red, exceeding the leaves. Drupes obconic, ⅛ in., red or yellow 3. G. flavida. Tall and stout, sometimes 12 in. high. Leaves ovate or oblong. Fruiting scape equalling the leaves or longer. Drupe obconic, ⅙ in., red 4. G. prorepens. Leaves orbicular-cordate, sharply and minutely toothed. Scapes shorter than the leaves. Drupes 1/10 in., oblong 5. G. densiflora. Leaves narrow-ovate to lanceolate, acute, cuneate at the base, coarsely dentate 6. G. dentata. Leaves thick and fleshy, broadly ovate, obtuse, cuneate at the base, crenate-lobed 7. G. arenaria. Very stout and coriaceous. Leaves deltoid-ovate, minutely toothed, cuneate at the base 8. G. Hamiltoni.
4. Callitriche, Linn.
Perfectly glabrous slender herbs, usually growing in wet places, often aquatic. Leaves opposite, linear or obovate-spathulate, quite entire, the upper ones often crowded or rosulate. Flowers monœcious, minute, axillary, solitary or rarely a male and female in the same axil, without perianth. Male flowers of a single stamen subtended by two minute bracts; filaments slender, elongated; anther 2-celled, cells confluent above. Female flowers with or without the 2 bracts. Ovary sessile or shortly stalked, 4-celled; ovules solitary in each cell; styles 2, elongated, stigmatic throughout their length. Fruit flattened, indehiscent, 4-lobed and 4-celled, ultimately separating into 4 1-seeded carpels.
A genus of very doubtful affinity, now often placed in the vicinity of the Euphorbiaceœ. The species are estimated at from 1 or 2 to 20 or 30, according to the different views of authors.
Fruits not winged, edges almost obtuse, groove between the carpels shallow. 1. C. antarctica. Fruits slightly winged, edges sharply keeled, groove between the carpels rather shallow 2. C. verna. Fruits broadly winged, wings pale, groove between the carpels deep 3. C. Muelleri.