Amyema scandens (Tiegh.) Dans.

Distribution Map

Neophylum scandens Tieghem, Bull. Soc. Bot. France 41 (1894) 509. - Amyema scandens (Tieghem) Danser, Bull. Jard. Bot. Buitenzorg III, 10 (1929) 299. - Type: Balansa 498 (holo P; iso P), New Caledonia, Prony Bay, ix.1868.
Doubtful species provisionally included here:

Loranthus schultzei Krause, Bot. Jahrb. Syst. 57 (1922) 478. - Amyema schultzei (Krause) Danser, Bull. Jard. Bot. Buitenzorg III, 10 (1929) 299. - Type: Schultze 305 (B, not extant), New Guinea, Sepik R., bivouac 48.

For descriptions and extensive further synonymy see Danser, Bull. Jard. Bot. Buitenzorg III, 11 (1931) 354, under A. verticillifolia; ibid. 14 (1936) 92; Barlow; Austral. J. Bot. 22 (1974) 583. The following taxa are excluded from this synonymy: Loranthus caudiciflorus, L. gigantifolius, L. plicatulus, Amyema cephalanthera, A. duurenii, A. ovariosa, and A. scandens subsp. crassifolia.

The species description by Barlow (1974) is amended as follows: Glabrous or rarely the inflorescence and flowers shortly and sparsely tomentose. Stems usually robust and distinctly lenticellate, enlarged at the nodes, terete. Leaves verticillate, mostly in whorls of 5-8, rarely quaternate; lamina very variable, lanceolate to ovate or rarely broadly ovate or obovate, 5-20 cm long, 2.5-7 cm wide, thinly to thickly coriaceous, dull on both sides or with the upper surface somewhat glossy, attenuate, cuneate or rarely truncate at the base into a petiole 3-10(-15) mm long, sometimes undulate at the margin, mostly acute or obtuse or less often rounded at the apex; venation pennate, mostly obscure except for the midrib which is raised below. Inflorescences several at the nodes and often on the epicortical runners; peduncle 6-12 (-30) mm long, 0.8-1.5 mm thick; rays 4-8, (3-)4-10 mm long; flowers all sessile in the mads; bracts triangular, c. 1 mm long, rounded at the apex, forming a small spreading involucre below the mads. Ovary funnel- to barrel-shaped, 2-3 mm long; calyx limb truncate, 0.5-1 mm long, erect or slightly funnel-shaped. Corolla in the mature bud slender, (20-)25-40 mm long, usually acute or shortly rounded, 5- or 6-merous. Anther (2.5-)3-4 mm long, usually about one third as long as the free part of the filament. Stigma knob-like, about 1.5 times wider than the style. Fruit ellipsoid to obovoid, 7-10 mm long, crowned by the calyx limb and often by long persistent styles.

Amyema scandens is recorded from New Guinea and New Caledonia (including Lifu and Isle of Pines) (fig. 14; 105 collections seen), at elevations from sea level to 1600 m. The species occurs in primary and secondary rain forest and open humid forests, parasitic on a wide range of hosts including Calophyllum, Eugenia, Garcinia, Nothofagus, and Terminalia.
The Amyema scandens species complex can be identified in the Papuasian region by the inflorescence of a 4- to 8-rayed umbel of triads with all flowers closely sessile in an equidistant arrangement. In addition to A. scandens, the complex includes A. arthrocaula, A. canaliculata, A. caudiciflora, A. cercidioides, A.friesiana, A. plicatula, and A. triantha. For further discussion on the two species accepted here as A. caudiciflora and A. plicatula, see notes under those species. Within the complex A. scandens can be identified by its leaves, which are verticillate and mostly in whorls of 5-8 (rarely quaternate), petiolate, flat, and mostly lanceolate to ovate. The corolla is consistently described as red, in shades ranging from pale to dark and from bright to dull.

The Amyema scandens complex is centred in New Guinea, and extends southeastwards to Australia and New Caledonia. To the west, its occurrence in Borneo represents a significant disjunction (see note under A. triantha). Half of the species in the complex are relatively localized in New Guinea and are apparently young endemics which have differentiated from the major more continuous body of variation as the rapid evolution of landforms created a greater diversity of niches to be occupied. They differ primarily in vegetative characters including phyllotaxy, petiole development, and leaf shape and texture. Apart from the triads of sessile flowers, the species have few specialized characters, and thus present a relatively generalized facies for the genus. As a whole, the complex appears to comprise vigorous robust biotypes which have occupied a range of habitats, and from a lowland base have reached some remote localities.

Amyema scandens itself has become the most abundant loranth in New Caledonia, presumably reaching there by dispersal from New Guinea. The most common biotype in New Caledonia is one with relatively small, ovate, rounded leaves 7-10 cm long, suggesting that some local differentiation has taken place. The New Guinean specimens mostly have longer, lanceolate, acute or obtuse leaves, which may represent the ancestral state of the species. Many New Caledonian specimens also show this state, so that the full range of variation of the species can therefore be found in New Caledonia. Variation between the larger- and smaller-leaved biotypes is continuous and no infraspecific taxa have been distinguished.
The holotype of A. schultzei (B) is no longer extant No isotypes are known, and no other specimens were referred to the species by Danser. The species is clearly a member of the A. scandens complex, and from the descriptions and illustration appears to be con specific with A. scandens itself. In the absence of specimens this cannot be confirmed, and the species must remain doubtful.

Distribution Map (Barlow 1974)

Description (Barlow 1974)

Synonomy

Glabrous or with the calyx very shortly and sparsely brown- or white-tomentose. Stems rohust, often conspicuously lenticellate. Leaves usually verticillate with 3-4-(8) leaves in the whorl, sometimes opposite; petiole ahsent or up to 2 cm long; lamina very variahle, narrow lanceolate to hroadly ovate, 8-20-(30) by (1.5) - 4- 6-(15) cm, thick or thin, sometimes undulate, attenuate to slightly cordate at the base, acute and shortly mucronate to rounded at the apex; venation always pennate, distinct or obscure. Inflorescences few to several at the nodes or on the runners; peduncle (1)-5-25 mm long; rays 5-8, 6-10 mm long; triads with all flowers sessile; hracts spreading, rounded, 1-2 5 mm long, shortly united at the margins into an involucre under each triad. Calyx cylindrical funnel-shaped or barrel-shaped; limb erect, truncate or weakly toothed, 07-1 3 mm long. Corolla in the mature hud slender, sometimes clavate, acute or ohtuse, 20-30-(38) mm long, 5- or 6-merous. Anthers 1-2.5 mm long; free parts of the filaments 5-6 times as long. Stigma knob-like, about 1.5 times as wide as the style.

Occurrence. New Guinea, New Caledonia and New Hebrides (Fig. 3), sea level to 2500 in altitude.

Amyema scandens is at the core of a complex within which there is a great deal of variation, and in which it is very difficult to recognize limits of species. Some of the extreme variants have been circumscribed as distinct species (A. angulare, A. canaliculatum, A. cercidioides, A. obovarum and A. pentactis). Each of these is based only on a single collection, and their constancy is therefore not known. However, each of these segregates occurs within the range of A. scandens, and is sharply distinct from material of A. scandens from the same area. The widespread species A. friesianum is probably also close to the A. scandens complex.

Within the polymorphic Amyema scandens three distinct forms may be distinguished, and because these are geographically discrete and apparently allopatric they have been treated as subspecies. Many specimens have been examined that have characters intermediate between two subspecies, or that resemble one subspecies but show a trend towards another. The intermediates, in fact, constitute the largest single group of specimens distinguished. Because of these strong indications of hybridization andlor clinal variation, it appears that there is no effective reproductive isolation between the entities recognized, and it does not seem appropriate to accord them specific status.

Key to Subspecies of Amyema scandens

1. Leaves distinctly petiolate, 7-15 cm long 2
1. Leaves sessile or nearly so, 9-25 cm long. Leaves usually regularly quaternate 23b. Subsp. crassifolium
2. Leaves scattered-ternate, elliptical to ovate, rounded at the apex 23c. Subsp. plicatulum
2. Leaves usually in regular whorls of 4-8, lanceolate to oblong, acute to rounded at the apex but usually with a small mucro 23a. Subsp. scandens

23a. Subsp. scandens
Synonyms: all names listed in synonymy under Amyema scandens with the following epithets: scandens Tiegh., rotundifolium Tiegh., vieillardii Tiegh., grandifolium Tiegh., pancheri Tiegh. lanceolatum Tiegh., luteum Tiegh., acutifolium Tiegh., rubrum Tiegh., fatifolium Tiegh., baudouinii Tiegh., lanceolatifolius EngI., neocaledonicus Schlecht., pustulatus S. Moore, glaucescens S. Moore, angustiflorus S. Moore and verticillifolia Krause. Illus. Dans. Bull. Jard. bot. Buitenz. 11: 343, Fig. 11, 1-n.

Leaves in regular or slightly scattered whorls of 4-8; petiole distinct, more or less terete, 05-2 cm long; lamina lanceolate to oblong, 7-15 by 2.5-3.5-(4.5) cm, attenuate at the base, acute obtuse or rounded at the apex but usually with a small mucro; venation pennate with the midrib distinct on both sides and raised below and the other venation obscure. Infiorescences slender; peduncle c. 15 mm long. Calyx slightly funnel-shaped. Corolla 30-38 mm long.

Occurrence. New Caledonia, Isle of Pines, Island Lifu and New Hebrides (Fig. 3), up to 1100 m altitude. Also recorded from four widely separated localities in New Guinea (Fig. 3), sea level to 260 in altitude.

Representative Specimens. WEST IRIAN: Wissel Lakes region, biv. Praun to Poero, trip from post to Boebeiro, Fyma 5433, Oct. 1939 (L). EASTERN NEW GUINEA: Penzara, between Morehead and Wassi-Kussa Rs., Western Div., Brass 8345, Dec. 1936 (CANB; L); Oomsis logging area, 260 m alt., Henty NGF 13694, Sept. 1961 (CANB; L). NEW CALEDONIA: R. Blanche, c. 30 miles E. of Noumea 200 m alt., McMillan 5126, 21.vii.1952 (L); Mt. Mou, 1050 m alt., MeMillan 5010, 26.vi.1952 (L); Mt. Dior, lower slopes, Chambers 2796, Aug. 1963 (AD); Plaine des Lacs, McKee 2375, 9.iv.1955 (L). NEW HEBRIDES: Ipota, Eromanga, Bernardi 13188 (L).

Amyema scandens subsp. scandens and Amylotheca pyramidata have been reported in New Caledonia by several authors to grow independently in the soil before becoming parasitic on the host (cf. Menzies and McKee 1959, in which the habit of the specimen McKee 2375 is described in some detail). Unfortunately no details are known about the growth and development of the root system. The situation may in fact be comparable with that in Gaiadendron punctatum (R. & P.) G. Don (Kuijt 1963, 1964). In that species, a plant may grow epiphytically or as a terrestrial shrub or tree. The terrestrial stage may occur secondarily when a plant growing aerially spreads down the host and reaches the ground.

23b. Subsp. crassifolium Barlow, subsp. nov.
Type-New Guinea, Western Highlands, Lagaip Valley, Kepilam Village, c. 2480 m alt., Hoogland and Schodde 7243, 30.vii. 1960 (CANB 84223, holotype; L 96120366).

Rami robustissimi, juniores conspicue lenticellati. Folia pleruinque regulatim quaternata (raro dissita); lamina crassa, late lanceolata vel elliptica, 10-25 cm longa, 3.5-10 cm lata, apice acuta vel rotundata, costa infra prominenti cetero obscuro, basi in petiolum crassum teresque 0-3 mm longum contracta. Inflorescentiae aliquot vel multae in axillis ortae, pleruinque robustae; pedunculus 10-18 mm longus; radii c. 8 mm longi. Calyx cylindricus vel leviter cupiforme, ad limbus constrictus. Corolla 25-30 mm longa.
Stems very robust, the young ones conspicuously lenticellate. Leaves mostly regularly quaternate (rarely scattered); petiole thick, terete, 0-3 mm long (i.e. leaf sessile or nearly so); lamina broad lanceolate to ovate, 10-25 by 3.5-10 cm, thick, contracted at the base (rarely attenuate), acute or rounded at the apex; venation pennate, obscure except for the midrib prominent below. Inflorescences several to many at the nodes, mostly rather robust; peduncle 10-18 mm long; rays c. 8 mm long. Calyx cylindrical or slightly barrel-shaped, constricted at the limb. Corolla 25-30 mm long.

Occurrence. Eastern New Guinea highlands (Fig. 3), 1500 to 2500 in altitude.

Representative Specimens. EASTERN NEW GUINEA: Above Bakaia, c. 15 miles SE. of Garaina, Morobe Dist., c. 2130 m alt., Hartley 12735, 23.i.1964 (CANB; L); Mt. Tafa, Central Division, 2300 m alt., Brass 4125, May-Sept. 1933 (L).

23c. Subsp. plicatulum (Krause) Barlow, comb. et stat. nov.

Loranthus plicatulus Krause. Nov. Gum. 14:102(1923); Amyema plicatula (Krause) Dans. Bull. Jard. bot. Buitenz. 10: 298 (1929); 11: 342 (1931). Type-West Irian, Pionierbivak, 70 m alt., Lam 641, 16.vii.1920 (L 926134837, holotype; K; U).

Amyema ovariosa Dans. Bull. Jard. bot. Buitenz. 11: 340, illus. Fig. 9, dd (1931). Type-West Irian, Pionierbivak, 50 m alt., Docters van Leeuwen 9383, June 1926 (B, lectotype, not seen; L). For syntypes, see above.

Leaves scattered-ternate; petiole distinct, 0 8-1.5 cm long; lamina elliptical to ovate, 9-13 by 5-7 cm, abruptly contracted to attenuate at the base, strongly undulate at the margin, rounded at the apex. Inflorescence rather slender; peduncle 12-22 mm long. Calyx slightly funnel-shaped.

Occurrence. West Irian (Fig. 3), sea level to 70 in altitude.

Representative Specimens. WEST IRIAN Aria near Oeta, 4 m alt., Aet (exp. Lundquist) 362, 27.vi.1941 (L); Sekoli, Hollandia, Noesi BW 8127, 20.ii.1960 (L).

Intermediate Forms

Many of the specimens of Amyema scandens examined in the present study have been treated as intermediates between the subspecies recognized. They are all from New Guinea, and are mostly from the mountains at middle elevations (1000-2000 m). The specimens here treated as intermediates include the types of four species (see below).

Selected Intermediate Specimens. WEST IRIAN: Nordrivier near Geitenkamp, Versteeg 1473, 10.vii.1907 (L, type of Loranthus caudiciflorus Lauterb.; K; WRSL); Mamberamo R. to Doorman Top, 1450 m alt., Lam 1875, 2.xi.1920 (L, type of Loranthus gigantifolius Krause); 18 km NE. of L. Habbema, 2200 m alt., Brass 11299, Nov. 1938 (CANB). EASTERN NEW GUINEA: Wuroi, Oriomo R., Western Div., 30 m alt., Brass 6023, Jan-Mar. 1934 (L, type of Amyema cephalanthera Dans.); Ukua Estate via Kairuku, van Duuren, Feb. 1963 (BRI, holotype of Amyema duarenil Barlow); Buko Ck. 3 miles from Gurakor, Morobe Dist., 450 m alt., Millar NGF 14450, 11.i.1962 (CANB).

Amyema scandens (as A. cephalanthera). An intermediate form. A - tip of twig with leaf. B - inflorescence. C - corolla with stamens. From Danser (1936, Brittonia 2:131-134).

Amyema scandens (as A. caudiciflora). An intermediate form. A - inflorescence. B - flower. C - two petals with stamens. From Danser (1931).

Amyema scandens (as A. ovariosa). Inflorescence. From Danser (1931).

Amyema scandens ssp. scandens (as A. verticillifolia). A - extremity of a twig with leaves. B - flower, of which two petals have been removed. C - older, flower-bearing twig. From Danser (1931).

Amyema scandens ssp. scandens. New Caledonia. Photo by Lytton Musselman.

Specific Locality Information

Amyema scandens

updated 18 January 2007