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Synonymy of Hildegardia

Introduction

Hildegardia is a genus of 12 species of malvaceous trees, placed in subfamily Sterculioideae/tribe Sterculieae. It has a pantropical distribution (West Africa, East Africa, Madagascar, southern India, Philippines, Indonesia, northern Australia and Cuba). The genus was introduced in 1832 [1] and revised in 1954 [a]. Additional species have be described in or tranferred to the genus in subsequent years. The type species is Hildegardia populifolia [2] (Roxb.) Schott. & Endl.

[Note: Kubitzki and Bayer [3] and Zaborsky [4] recognise an additional species, Hildegardia major, from China. I follow the Flora of China [5] in placing this species in Firmiana.]

The genus is the type of Reichenbach's [b] (currently unrecognised) suprageneric taxon Hildegardieae.

The genus is distinguished from other genera of Sterculieae by the combination of the traits of indehiscent (not dehiscent) and thin, membraneous or papery (not thick, leathery or woody) fruits. Like the other genera of the tribe its flowers lack petals, and also lack an epicalyx, but possess an androgynophore.

The leaves are thin, broadly ovate, unlobed or slightly lobed, cordate at the base, palmately nerved, with entire margins, and sometimes with domatia. The inflorescence is composed of raceme like panicles at the end of the shoots. The flowers are polygamous, some being hermaphrodite, others unisexual. The calyx is tubular, 4- or 5-lobed, usually petaloid and reddish in colour, and persistent in fruit. The stamens number twice or thrice the number of sepals, and are united in a longish androgynophore, at the end of which the anthers are sessile, and clustered around the carpels. The anthers are 2-locular. The carpels number 5, borne on a short stalk, and soon separate from each other. They are uniovulate or biovulate. In fruit they are free, long-stalked, and indehiscent, with a membranous and reticulate coat.[2, 3]

The African and Malagasy species appear to form a natural group in which the calyx is tubular, and only shortly divided at the apex, and which flower when the plant is bare of leaves [6]. The former constrasts with the deeply divided calyx and reflexed sepals of Hildegardia australiensis and Hildegardia populifolia, while the flowers of Hildegardia cubensis are intermediate. A study of DNA sequences from Sterculioideae [c] found that Hildegardia and Firmiana did not form mutually distinct clades, implying that a revision of these two genera is necessary.

Hildegardia millenari, mention of which can be found on the WWW, is fictional. Hildegardia is also a genus of grasshoppers.

Hildegardia ankaranensis (Arènes) Kosterm.

Hildegardia ankaranesis is in found deciduous forest on the hilla and plateaux of the northern tip of Madagascar, most frequently in Ankarana reserve, from which the specific epithet is presumably taken [7].

It is a large tree. The trunk can attain a diameter of 1m or more [7].

The leaves are long petiolate, broadly ovate or suborbicular to 17 × 15 cm, palmately 7–9-nervate, cordate at the base and weakly 3-lobed. The lobes are variably acuminate, in some leaves only the central lobe being so. The flowers are tubular and orange-red in colour, the individual sepals being fused almost to the apex. The fruit is composed of 5 follicles. The 2-seeded follicles are relatively large (9 × 6½cm), more or less flattened, with a thick coriaceous pericarp. Their indumentum is velutinous. It is brown or ferriginuous on the outside, and fawn-coloured, and composed of stellate hairs on the inside [7].

Sterculia ankaranensis Arènes is a synonym of Hildegardia ankaranensis.

Hildegardia australiensis G.J.Leach & Cheek

A recently (1991) described deciduous species, related to Hildegardia sundaica, from the Western Arnhem Land plateau in Australia's Northern Territory.

It is a deciduous tree growing to 7-10m in height. The bark of the trunk is mostly smooth, with fine lengthwise fissures, and light grey in colour. Young wood is covered with white, flaky, waxy coating. The blade of the leaf is simple and palmately 7-nerved [8].

In common with several other species of this genus, and also with the Australian endemic genus Brachychiton, the flowers are borne during the leafless period.The species is apparently dioecious. Female flowers were not available when the species was described, and no subsequent description has come to hand. The calyx of the male flowers is composed of 4 or 5 reflexed strap-like orange to red sepals, divided almost to the base, where they are fused into a cup like structure. The individual sepals are 9-11mm long and 2mm wide. Their lower surface is covered with peltate scales. A cluster of 8-10 yellow anthers is borne at the summit of a dull yellow stalk, described by Leach and Cheek as an androphore. This is slender at its base and apex, and swollen in the middle. These male flowers are highly scented. [8, 9]

The fruit is composed of 4 or 5 inflated and winged fruitlets. Each fruitlet contains 1 or 2 spherical seeds. [8]

Hildegardia barteri (Mast.) Kosterm.
Igbo Ufuku
Yoruba Eso, Okurugbedu, Shishi
Hausa Kariya

Hildegardia barteri is found in dry tropical forest in West Africa from the Ivory Coast to southeastern Nigeria. It is a pioneer species, and may flower as early as its 2nd year. It is tree growing to 10-13 m high. The branches are thick, and are covered with a loose, smooth, reddish-yellow bark. The leaves are 10 to 20 cm long, orbicular, cordate at the base, acuminate at the apex, palmately 7-nerved, with a sinuous margin. They are glabrous on both surfaces, or with a few stellate hairs on the lower surface. The petioles are 7-10 cm long. The tree is leafless is the dry season. [10]

The flowers are borne before the new leaves. The inflorescence is a loose branching panicle, with numerous flowers. The peduncles are shorter than the leaves, and the indiividual pedicels 6-12 mm long, and jointed. The calyx is 18 mm long, leathery, tubular, gibbous at the base, contracted in the middle and terminated into 5 short, ovate, lobes, with acute apices. It is downy externally, and glabrous internally, except for a few villous hairs pointing downwards at the base. The staminal column is appreciably shorter than the calyx. The fruit is borne on a long gynophore, which is twice the length of the persistent calyx, and is composed of 5 spreading, membranous, 1-seeded carpels, each about 5 cm in length. The seeds are smooth. [10]

The wood, like that of many other Malvaceous trees, is light. It is used for floats for fishermen's nets [10], and is also used in the production of household equipment and furnishings. The seeds are a source of condiments. The tree is also a source of fibre and gum, perhaps from the bark.

Hildegardia barteri may be propagated by cuttings and bud grafts, as well as by seed.

Hildegardia barteri has been observed to be susceptible to infection by cacao swollen stem virus (CSSV). (This virus is restricted to West Africa, and the natural host is presumably nor Theobroma cacao, and might indeed be Cola and Hildegardia.

Hildegardia barteri has a diploid chromosome count of 40.

Synonyms of Hildegardia barteri include Clompanus barteri Kuntze, Erythropsis barteri (Mast.) Ridley, Firmiana barteri Schum., Sterculia barteri Mast. and Tarrietia barteri Hochr..

Hildegardia cubensis (Urb.) Kosterm.
Spanish Guana
German Guana-baum

Hildegardia cubensis is endemic to Cuba, with a restricted distribution in lowland semi-deciduous forest on rocky limestone soils in the east of that country. It is threatened by habitat loss.

The leaves have long, slender, petioles (13 cm long, 3.3 mm thick). The blades are large (20 cm in diameter), and are suborbicular, deeply cordately incised at the base, 9-nerved, shortly acuminate at the apex, with an entire margin.

The flowers appear with the leaves [6], in March. They are hermaphrodite, and yellow in colour. The calyx is divided for about half its length. The fruit is composed of single-seeded samaras, which are initially yellowish, and turn first red, and later greyish brown, as they mature.

Sterculia cubensis Urb. is a synonym of Hildegardia cubensis.

Hildegardia dauphinensis J.G.Zaborsky

This species, described in 2009, is known from a single specimen located near Fort Dauphin (Taolagnaro) in the south east of Madagascar. It is similar to Hildegardia perrieri, from which it differs by the absence of revolute leaf margins, and the presence of an indumentum of highly (18-22) branched stellate hairs [4].

Hildegardia erythrosiphon (Baill.) Kostermm
Malagasy Aboringa, Boaloaka, Boaloaky, Boramena, Tamotamokazo, Vinoa, Vonoa

Hildegardia erythrosiphon is found in the deciduous forest of western Madagascar, where it is weakly associated with calcareous soils. It is a tall tree, with outspread, near-horizontal branches. The leaves are long petiolate, broadly ovate, palmately 7-nervate, unlobed, or weakly 3–5-lobed, cordate at the base, somewhat acuminate, and with a revolute margin. The blades are glabrous or glabrescent above, and densely covered with an indumentum of white, stellate, hairs underneath. The calyx is red or orange-red, streaked with orange. The style is similar in colour to the calyx, but the capitate stigma is yellow. The fruit is apocarpous, composed of 5 short-stalked, yellowish-green, inflated pods, each containing 1 or 2 seeds [7].

Arènes [7] divided the species into several subspecies, varieties and subvarieties, varying in the hairiness and shape of the calyx. Zaborsky [4] argues that the intergradation occurs between these forms, and that Arènes' infraspecific taxa are not distinguishable.

Synonyms of Hildegardia erythrosiphon include Erythropsis erythrosiphon (Baill.) Ridley, Sterculia erythrosiphon Baill. and Tarrietia erythrosiphon Hochr..

Hildegardia gillettii L.J. Dorr & L.C. Barnett

A recently described (1990) species from Somalia [6]. It is similar to Hildegardia barteri and Hildegardia migeodii, but differs in the presence of a stellate pubescence on the petioles, the presence of a sparse stellate and dense glandular pubescence on the pedicels, shorter petioles (3½-5 cm long), and the presence of only a short stipe below the calyx. Dorr and Barnett also contrast its undulate or entire leaf margins with the revolute leaf margins of Hildegardia barteri and Hildegardia migeodii; however other sources describe those species as possessing sinuous and undulate margins respectively, so there is some doubt as to the validity of this as a key character. Hildegardia gillettii is found in bushland, as opposed to the woodland habitat of the other two species.

Hildegardia gillettii was described from a single specimen, and fruit material was not available. Additionally the flowers of that specimen were interpreted as immature, leaving some doubt as to the nature of the mature androecium and gynoecium, and whether the flowers are, as implicitly stated, hermaphrodite.

Hildegardia gillettii is a tree, known to reach at least 10 m in height. The leaves ares short-petiolate, broadly ovate, not lobed, large (12-13 cm long, and marginally less in width), cordate and 9-veined at the base, obtuse or acute, not acuminate, at the apex, with undulate or entire margins. They are glabrous on both surfaces, except for the presence of tufts of hairs in the axils of the veins on the undersurface. The inflorescence is an axillary raceme, borne towards the ends of the branches. The flowers are bracteate, 2-3 mm long bracts, with stellate and glandular pubescence, subtending the pedicels. The calyx is red.

Hildegardia merrittii (Merrill) Kosterm.

This species, from Mindoro in the Philippines, and perhaps from elsewhere in that country, is a large deciduous tree, reaching a height of 30 m, and a trunk diameter of 90 cm. The leaves are large (blade up to 18 cm long and about as wide), long-petiolate (petioles 20 cm long), broadly ovate to orbicular-ovate, very broadly rounded and deeply and narrowly cordate at the base, palmately 7- or 9-nerved, acuminate at the apex, with an entire margin, a coriaceous or thickly chartaceous texture, and a glabrous surface when mature. The follicles of the fruit contain one or two seeds. They are inflated, tardily if at all dehiscent, and narrowly oblong-ovate, with an acute base and obtuse apex. They are glabrous, thickly chartaceous in texture, 8 to 9 cm long, and 4 cm wide. [11]

Firmiana merrittii Merr. is a synonym of Hildegardia merrittii.

Hildegardia migeodii (Exell) Kosterm.

This species from Tanganyika, also extending into Mozambique, varies between a 2 m high shrub and a 15 m high tree. It is glabrous, except for the flower and seeds. The bark is greyish. The leaves are up 16× 18 cm in size, with an entire or undulate margin, 7-nerved at the base, and possess an obtuse apex. The petiole may be up to 30 cm (1 ft) long. The flowers are borne in axillary racemes c. 12 cm long, borne near the ends of the branches, and appearing before the leaves. They are salmon-coloured. The pedicels are 3-4 mm long, and are articulated near the apex. The calyx is tubular, 2 cm long by 0.5-0.8 cm across, and is somewhat swollen at the base. It is terminated by 2-3 mm long lobes, which are triangular and acute at the apex and may be either erect or reflexed. The exterior is glabrous, the interior villous at the base and pubescent above. In the male flowers the androphore is about 2.5 mm long, and is pubescent except on those parts protruding beyond the calyx tube. In the female flowers the gynophore is about 7 mm long, and is densely pubescent except near the apex. The ovary is ovoid, glabrous, and composed of 5 coherent carpels. The stigma-lobes are recurved and subsessile. The fruiting carpels are 5.5 cm long by 2 cm in diameter, borne on an elongated gynophore 3 cm in length. They are elliptic, glabrous, purplish, membranaeous, with 1 cm long basal stipe. Each contains 1 or 2 seeds, which are c. 0.7 cm in diameter, globose and pubescent. [12]

Synonyms of Hildegardia migeodii include Erythropsis migeodii (Exell) Ridley and Firmiana migeodii Exell.

Hildegardia perrieri (Hochr.) Arènes
Malagasy Afobonona, Vonoana

Hildegardia perrieri is found in the wet forests of eastern Madagascar, where it is one of the few deciduous species. It is a large tree, reaching 20 or 30m. The leaves are broadly ovate, palmately 7–9-nerved at the base, shortly acuminate at the apex, and slightly cordate at the base, with revolute margins. The upper surface is glabrescent, and the lower surface covered with ferruginuous hairs. The flowers are yellow-green. The fruits are green with dark red stripes [7].

Tarrietia perrieri Hochr. is a synonym of Hildegardia perrieri.

Hildegardia populifolia Schott & Endl.

Hildegardia populifolia is a critically endangered species from tropical dry evergreen forest of the Eastern Ghats of Tamil Nada and Andhra Pradesh [d]. It is a smooth-barked deciduous tree. The leaves are long petiolate (petiole 5-12 cm long), large (blade 7-10 ×10 cm), orbicular, palmately 7-nerved, deeply cordate at the base, acuminate at the apex, and with entire margins. Individual plants are polygamous, but the sources available to me do indicate whether they are andro-, gyno- or trimonoecious. The scarlet flowers are borne in April. They form axillary and terminal panicles, which are shorter than the leaves (up to 15 cm long). The flower buds are oblong, The calyx is small (6 mm long), scarlet, with the sepals linear-spathulate and divided nearly to the base. It is downy externally. There are 10 stamens. The hispid ovary is avoid, tapering to a short style, with a 5-lobed stigma. The fruit is apocarpous, composed of 5 follicles. These follicles are up to 10 cm long by 5 cm broad, obliquely lanceolate in outline, membraneous, inflated, and strongly veined, with 2 seeds. The seeds are ovate-oblong, pale brown, and 15-20 mm long. [13, 14]

The stems of Hildegardia populifolia have been used as a source of fibre, and the bark as a herbal medicine. Papers have been published on the fibres and their use as component in fibre-resin and fibre-plastic composite materials. [e, f, g, h, i, j, k]

Synonyms of Hildegardia populifolia include Clompanus populifolia Kuntze, Firmiana populifolia Terrac., Hildegardia candolleana Steud., Hildegardia candollei Schott & Endl. and Sterculia populifolia Roxb. & Wall..

Hildegardia sundaica Kosterm.

A species from Sumbawa in Indonesia, and perhaps from elsewhere in that country.

Images

References

  1. Schott & Endlicher, Meletemata Botanica 33 (1832)
  2. Hutchinson, J.B., The Genera of Flowering Plants 2: 536-567 (1967)
  3. Kubitzki & Bayer, Malvaceae, in Kubitzki & Bayer, Fam. Gen. Vasc. Plants V: (2003)
  4. Zaborsky, Hildegardia dauphinensis (Malvaceae, Sterculioideae): a new species from southeastern Madagascar, Adansonia 31(1): 143-148 (2009)
  5. Wu, Z. Y., P. H. Raven & D. Y. Hong, eds, Flora of China 12: 263-330 (2007)
  6. Dorr & Barnett, A New Species of Hildegardia (Sterculiaceae) from Somalia, Kew Bulletin 45(3): 577-580 (1990)
  7. Arènes, Flore de Madagascar et les Comores. Famille131. Sterculiaceae (1959)
  8. Cheek, M.R. & Leach, G.J., Hildegardia (Sterculiaceae) new to Australia, Kew Bulletin 46(1): 72 (1991)
  9. Top End Native Plant Society Newsletter Oct-09 (2009)
  10. Masters, Maxwell T. in Oliver, D., Flora of Tropical Africa 1: 218-219 (1868)
  11. E.D. Merill, New or Noteworthy Philippine Plants X, Philippine Journal of Science 9(4): 314 (1914)
  12. Wild, H., Sterculiaceae, in Exell & Meeuse, Fl. Zambes. 1: 582-584 (1961)
  13. Masters, Maxwell T. in Hooker, J.D., The Flora of British India 1: 361 (1875)
  14. Rao & Pullaiah, Ethnobotanical Studies on Some Rare and Endemic Floristic Elements of Eastern Ghats-Hill Ranges of South East Asia, India, Ethnobotanical Leaflets (2007)

Bibliography

  1. Kostermans, A Note on Some African Sterculiaceae, Bull. Jard. Bot. Brux. 24(4): 335-338 (1954)
  2. Reichenbach, Handbuch des natürlichen Pflanzensystems 291: 1-7 (1837)
  3. Wilkie et al, Phylogenetic Relationships within the Subfamily Sterculioideae (Malvaceae/Sterculiaceae-Sterculieae) Using the Chloroplast Gene ndhF, Systematic Botany 31(1): 160-170 (2006)
  4. Sarcar & Sarcar, Status, botanical description, natural distribution zone, propagation practices and conservation efforts of Hildegardia populifolia (Roxb.) Schott & Endl.: A threatened tree species of dry tropical forests in India, Indian Forester 128(7): 757-770 (2002)
  5. Rajulu et al, Tensile Properties of Epoxy Coated Natural Fabric Hildegardia Populifolia , Journal of Reinforced Plastics and Composites 23(2): 217-219 (2004)
  6. Li et al, Completely biodegradable composites of poly(propylene carbonate) and short, lignocellulose fiber Hildegardia populifolia, Journal of Polymer Science B 42(4): 666-675 (2004)
  7. Rajulu et al, Effect of alkali treatment on properties of the lignocellulose fabric Hildegardia, Journal of Applied Polymer Science 90(6): 1604-1608 (2003)
  8. Rajulu et al, Mechanical Properties of Short, Natural Fiber Hildegardia populifolia-reinforced Styrenated Polyester Composites, Journal of Reinforced Plastics and Composites 24(4): 423-428 (2005)
  9. Rajulu et al, Tensile properties of natural fabric Hildegardia populifolia/polycarbonate toughened epoxy composites, Polymer Composites 25(6): 563-568 (2004)
  10. Guduri et al, Effect of alkali treatment on the flexural properties of Hildegardia fabric composites, Journal of Applied Polymer Science 102(2): 1297-1302 (2006)
  11. Rajulu et al, Tensile properties of ligno-cellulosic fabrics coated with styrenated polyester resin , Cellulose 10(2): 179-183 (2004)

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