Anthorrhiza
Anthorrhiza
Anthorrhiza Huxley & Jebb is a genus of myrmecophytic plants in the family Rubiaceae, endemic to New Guinea and its surrounding islands. The eight currently described species are predominantly epiphytic inhabitants of montane rainforests, although Anthorrhiza areolata also occurs terrestrially. All species develop a tuberous caudex containing internal cavities that are usually inhabited by ants. Within the genus, two morphologically distinct groups can be recognized: species with smooth or only sparsely spiny caudices, and species with densely branched, stellate spines on both the caudex and stems. Additional diagnostic features include sunken inflorescences and predominantly white flowers; only Anthorrhiza caeruleabears the unique turquoise-blue flowers within the genus.
Anthorrhiza bracteosa (Normanby, PNG)
Anthorrhiza bracteosaAnthorrhiza bracteosa Huxley & Jebb is an epiphytic species of the family Rubiaceae, which is found on the D’Entrecasteaux Islands and on Woodlark Island in eastern Papua New Guinea. It grows in rainforests from sea level up to an altitude of approximately 1,600 m . On Normanby Island, it also colonises low-growing vegetation on nutrient-poor soils, where it grows alongside Anthorrhiza areolata and Hydnophytum species. The cavities of the caudex are only occasionally inhabited by ants, but more frequently by cockroaches, beetles and other invertebrates.Characteristic of the species is the flattened spherical to cylindrical, spine-less caudex with numerous small entry holes. The few square shoots bear lanceolate to obovate leaves. The species name bracteosa refers to the strikingly large, papery to leathery bracts, which largely cover the sunken inflorescences and constitute a unique identifying feature of the species. The flowers are white, the fruits red.
Anthorrhiza camilla (Garassa, PNG)
Anthorrhiza camillaAnthorrhiza camilla Jebb is an epiphytic species of the Rubiaceae family, known exclusively from the Morobe Province in eastern Papua New Guinea. It grows as a low-growing epiphyte in shady, moss-rich montane rainforests at altitudes of 1,600–2,000 m. Unlike the other heavily spiny species of the genus, it prefers to inhabit the interior of the forest and sheltered locations. The species was named after Camilla Huxley-Lambrick , who, together with M. H. P. Jebb, described the genus Anthorrhiza .A characteristic feature of the species is a spherical caudex densely covered with golden-brown, star-shaped, branched spines. The shoots, which are also heavily spined, bear narrow, lanceolate leaves arranged in a terminal rosette. The small, sunken inflorescences have papery bracts that fall off early – an important distinguishing feature from Anthorrhiza chrysacantha. The flowers are whitish-green with yellow anthers; the fruits are yellow-orange. Among the spiny species, A. camilla particularly A. chrysacantha, but it also differs in having shorter spines and smaller inflorescences.
Anthorrhiza chrysacantha (Mt Kaindi, PNG)
Anthorrhiza chrysacanthaAnthorrhiza chrysacantha Huxley & Jebb is an epiphytic species of the family Rubiaceae, found in the montane rainforests of Central and Eastern Papua (Papua New Guinea). It grows in disturbed Nothofagus forests at altitudes of around 1,200–2,200 m, usually high up in the canopy, and is frequently sympatrous with Anthorrhiza caerulea . The caudices are regularly colonised by the ant Iridomyrmex scrutator .A characteristic feature of the species is a flat caudex that lies close to the substrate, bearing dense, conspicuous golden-brown, multi-branched, star-shaped spines. As the plant matures, several sturdy, densely spined and branched shoots emerge from the caudex, bearing lanceolate to obovate, leathery leaves. The depressed inflorescences are surrounded by a narrow, spiny margin of tissue and bear white flowers with long, narrowly tapering corolla lobes. In comparison to A. caerulea A. chrysacantha larger, golden-brown spines, smaller leaves with less conspicuous venation, and white rather than turquoise-blue flowers. The fruits are spherical, yellowish-orange berries.This species is absolutely breathtaking!It forms huge plants that grow on isolated trees at the summit of Mt Kaindi in Papua New Guinea. At first glance, the plants appear very similar to Anthorrhiza caerulea, but they are much larger, and the leaves are smaller and not wavy. Furthermore, A. chrysacantha plants produce several shoots per plant. In my opinion, this species is in a league of its own alongside Myrmecodia lamii, Hydnphytum kajewskii and Squamellaria major when it comes to its bizarre appearance!
Anthorrhiza echinella (Perikles Pass, PNG)
Anthorrhiza echinellaAnthorrhiza echinella Huxley & Jebb is an epiphytic species of the family Rubiaceae, found in the montane rainforests of eastern Papua New Guinea. It grows at medium to high altitudes as an epiphyte on forest trees and forms a spherical, densely spiny caudex with a system of cavities inhabited by ants.A characteristic feature of this species is the grey caudex, up to about 25 cm wide, with numerous irregularly star-shaped branches of spines. The species name echinella is derived from the Greek echinos (‘sea urchin’) and refers to the strikingly spiny appearance of the caudex. The sparsely branched shoots bear large, lanceolate to obovate, dark green leaves with a distinctly prominent midrib. In contrast to most other spiny species of the genus, the spines on the shoots are largely confined to the inflorescences. The depressed inflorescences bear whitish-green flowers. The fruits are orange to red-coloured berries.
Anthorrhiza recurvispina (?) (Missima Island, PNG)
Anthorrhiza recurvispinaAnthorrhiza recurvispina Huxley & Jebb is an epiphytic species of the family Rubiaceae, found in the Louisiade Archipelago in eastern Papua New Guinea. It has been recorded on the islands of Misima, Rossel and Sudest and grows in lowland rainforests and open hillside woodlands from sea level up to an altitude of around 300 m. The species’ locus classicus is on Rossel Island. The plants usually grow singly or in small groups alongside Hydnophytum and are regularly colonised by the ant Iridomyrmex scrutator . With a caudex up to 35 cm in diameter, A. recurvispina one of the largest species in the genus. The population on Misima Island differs from the populations on Rossel in several morphological characteristics and may possibly represent a previously undescribed species.A characteristic feature of the species is the spherical to slightly flattened caudex with numerous hook-shaped, star-shaped spines, to which the species name recurvispina (‘with recurved spines’). The sturdy shoots bear large, ovate to obovate leaves with long petioles. In contrast to Anthorrhiza echinella , the caudex is only sparsely spined, has significantly more entry openings, and the smaller inflorescences bear a few sturdy, slightly curved spines. The flowers are white, the anthers strikingly blue, and the fruits are red.
Anthorrhiza recurvispina (Rossel Island, PNG)
Anthorrhiza recurvispinaAnthorrhiza recurvispina Huxley & Jebb is an epiphytic species of the family Rubiaceae, found in the Louisiade Archipelago in eastern Papua New Guinea. It has been recorded on the islands of Misima, Rossel and Sudest and grows in lowland rainforests and open hillside woodlands from sea level up to an altitude of around 300 m. The species’ type locality is on Rossel Island. The plants usually grow singly or in small groups alongside Hydnophytum and are regularly colonised by the ant Iridomyrmex scrutator . With a caudex up to 35 cm in diameter, A. recurvispina to the largest species in the genus.A characteristic feature of the species is the spherical to slightly flattened caudex with numerous hook-shaped, star-shaped spines, to which the species name recurvispina (‘with recurved spines’). The sturdy shoots bear large, ovate to obovate leaves with long petioles. In contrast to Anthorrhiza echinella , the caudex is only sparsely spined, has significantly more entry openings, and the smaller inflorescences bear a few sturdy, slightly curved spines. The flowers are white, the anthers a striking blue, and the fruits are red.
Anthorrhiza areolata (Normanby, PNG)
Anthorrhiza areolataAnthorrhiza areolata Huxley & Jebb is a myrmecophytic species of the family Rubiaceae, found on the D’Entrecasteaux Islands in eastern Papua New Guinea. Unlike most species in the genus, it grows both epiphytically and terrestrially in nutrient-poor habitats, particularly on Normanby Island. The cavities in the caudex often contain water and are inhabited by various invertebrates, including cockroaches and beetles; there is as yet no evidence of colonisation by ants.Characteristic of the species is a spherical to flattened-spherical, thorless caudex with numerous small entry openings. The sparsely branched shoots bear lanceolate to obovate leaves. The species name areolata refers to the conspicuous, areole-like arrangement of the openings in the caudex. The sunken inflorescences bear white flowers; the fruits are red.Unfortunately, it is rarely possible to pollinate the flowers in cultivation, so that seeds are set only very rarely, which makes propagation very difficult.
Anthorrhiza caerulea (Mt Kaindi, PNG)
Anthorrhiza caeruleaAnthorrhiza caerulea Huxley & Jebb is an epiphytic species of the Rubiaceae family, found in the mountain rainforests of Morobe Province in Papua New Guinea. It grows at altitudes of around 2,000–3,000 m, mostly on large Nothofagus trees, where it is found in both the lower and upper parts of the canopy. The caudices are invariably colonised by the ant Iridomyrmex scrutator. The species is sympatric with Anthorrhiza chrysacantha.A characteristic feature of the species is the conical caudex with densely clustered, dark brown, star-shaped spines. One or two sturdy, densely spined shoots emerge from the caudex, bearing large, lanceolate to obovate leaves with distinctly prominent veins and slightly wavy margins. The depressed inflorescences are surrounded by a spiny margin of tissue and bear striking turquoise-blue flowers, a feature unique within the genus. Compared to A. chrysacantha A. caerulea smaller, dark brown spines, larger leaves with more prominent veins, and the characteristic turquoise-blue flowers, whilst A. chrysacantha is characterised by larger golden-brown thorns and white flowers. The fruits are elongated, egg-shaped, orange-coloured berries.Now available commercially for the first time!