Heteropyxis canescens – updating now!

General Info – Summary

This Tree is up to 15m high, with a straight or twisted trunk. Simple gland dotted aromatic narrow & entire Leaves lack stipules. Secondary veins arch towards the apex. Small whitish, 5-merous, scented & bisexual actinomorphic Flowers are in dense panicles. 5 stamens+free extending anthers. Two-locular ovary has 1 short style with a capitate stigma. Small Fruit: a nearly spherical capsule with small slightly winged seeds.

Description

Previous Names: Heteropyxis transvaalensis.

SA Tree No. 454.

Common names: (Afr) Boslaventelboom. (Eng) Lavender Tree, Forest Lavender-tree. (siSwati) Inkunzana.

Common names: (Afr) Basterlaventelboom, Boslaventelboom. (Eng) Bastard Lavender Tree, Lavender Tree, Forest Lavender-tree. (IsiZulu) Ikhuze. (siSwati) Inkunzana.

Family Myrtaceae (Myrtle and Eucalyptus family) has 130+ genera and 3 000+ species and includes the Australian genus Eucalyptus, as well as guava and clove. These mostly evergreen trees have simple Leaves that are leathery, usually entire, gland-dotted and usually opposite. Stipules are very small or absent. Flowers are regular usually bisexual and 4 or 5-merous. However, petals may be small or absent. The many Stamens are inflexed in the bud and Anthers are 2-thecous (with 2 pollen sacs). They usually open by lengthwise slits. The usually inferior Ovary has a simple Style with a capitate Stigma. The Fruit is a capsule or berry with a persistent Calyx. Local genera with trees on this website include Eugenia, Heteropyxis, Metrosideros (Western Cape) and Syzygium.

Name derivation: Heteropyxis – hetero – distinct or different; pyxis with a box like lid – referring to the capsule. canescens greyish – refers to ashen-grey – colour of hairs found on branches and underside of leaves. There are 3 species in Southern Africa. The other 2 are H. dehniae and H. natalensis.

Conservation: National Status: L C. (Least Concern). Assessment: 2005/02/23 (J.E. Victor). Note: this is a rare plant.

Tree

Young branches have fine grey hairs that persist until maturity. The Tree (photo 240) usually has a single, upright Trunk that branches high up. It is relatively narrow and usually 3-8m high tree but may reach 15m or more. The trunk may be straight or twisted. The Bark is silvery grey (photo 993) to brown most of the year. In early summer the bark flakes off in more or less oval discs, exposing attractive big pinkish blotches of the underbark (photo 186). This is similar to what occurs in Podocarpus falcatus. These blotches darken rather quickly and become grey with time (photo 993).

: 240. 2014/10/21. Walter Sisulu NBG. Photo: David Becking.

: 993. 2014/04/01. Walter Sisulu NBG. Photo: David Becking.

: 186. 2015/12/08. Walter Sisulu NBG. Photo: David Becking.

Leaves

The leathery and usually alternate or spirally arranged Leaves are simple (has a single blade which may have incisions that are not deep enough to divide the blade into leaflets). Leaves are narrowly elliptic to elliptic and up to about 14 x 3cm (photo 192). They are usually longer than those in Heteropyxis natalensis. Occasionally a red, orange or yellow leaf may appear. This weather dependent tree is evergreen or semi-deciduous. The leaves may change to an impressive orange/red after a cold spell (photo 816). The Upper surface is shiny (photos 192 & 132), dark green and hairless (photo 192). When the much lighter green Lower surface is observed with a good hand lens, gland dots and the persistent leaf hairs are visible (photos 194 & 193). In photo 192, the Secondary veins are raised on the lower surface and prominently contrast with those of the dark green leaves on the upper surface. Veins may be slightly pink and form an acute angle with the midrib. They then curve to follow the margin towards the Apex (photo 192). In this photo Net veining is loose and the apex tapers narrowly and may form a drip tip. Here the Base is narrowly tapering. Unlike Heteropyxis natalensis, these margins are rolled under on the underside where the raised secondary veins are also prominent. This Margin is entire (with a continuous margin, not in any way indented – photo 192). Petioles (leaf stalks) are up to 6mm long (photo 192). Stipules (basal appendages of the petiole) are rudimentary or absent. Crushed leaves are aromatic.

: 192. 2014/12/02. Walter Sisulu NBG. Photo: David Becking.

: 816M. 2015/08/11. Walter Sisulu NBG. Photo: David Becking.

: 132. 2014/06/03. Walter Sisulu NBG. Photo: David Becking.

: 194. 2014/12/02. Walter Sisulu NBG. Photo: David Becking.

: 193. 2014/12/02. Walter Sisulu NBG. Photo: David Becking.

Flowers

The scented, small, white, cream or yellow-green Flowers develop at branch ends in dense terminal Panicles (indeterminate, branched inflorescences with stalked flowers – photo 563). Each tiny flower is about 3mm long and rests on a soft and short hairy Pedicel (stalk of a single flower – photo 34). Here orange nectaries are visible. Flowers are actinomorphic (Regular, symmetrical. They are vertically divisible into similar halves by more than one plane passing through the axis) and perigynous (having sepals, petals, and stamens at the same level as the carpels: halfway up the superior ovary). The Calyx (is the outer whorl of floral envelopes and consists of leaf-like structures called Sepals at the flower base). Sepals protect the bud during flower development. They are cup-shaped with 5 persistent and imbricate (having regularly arranged, overlapping edges, like roof tiles photo 34). These sepal lobes are persistent (photo 16 & 981 under Fruit). The Corolla has 5 imbricate Petals (modified leaves). These arise from the inner rim of the Hypanthium (the cup-like receptacle usually derived from the fusion of floral envelopes and Androecium (male element), and on which the calyx, corolla and stamens develop). Petals are gland-dotted and fall away very early after pollination. Flowers are Monoecious (unisexual floral structures with functional male and female parts on the same plants). The Male parts have 5 free Stamens each with 2-locular Anthers (where the pollen grains are formed). The Filaments (the slender stalk that supports the anther) extend the anthers beyond the sepals (4 photos below). Thin Pollen grains are just visible on the right-hand side flower (photo 34). In the Female parts, the Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma) has a 2-locular Ovary that is almost spherical and contains numerous ovules. It ends in a swolen Stigma (the part of the pistil that receives the pollen) at the end of a short Style (the part of the pistil situated between the ovary and the stigma – photo 16 under Fruit). (Nov-Jan).

: 563. 2014/03/06. Walter Sisulu NBG. Photo: David Becking.

: 34. 2016/12/06. Walter Sisulu NBG. Photo: David Becking.

: 39. 2016/12/06. Walter Sisulu NBG. Photo: David Becking.

Fruit

The small, light brown, almost spherical Fruit (photo 16 – with unknown insect) is a Capsule (a dry fruit resulting from the maturing of a compound ovary, which usually opens at maturity by one or more lines of dehiscence). This capsule, which just protrudes past and, is partly enclosed by the persistent Calyx, measures up to 3 x 3mm. The fruiting pedicel (stork) is short and covered with soft grey hairs. The very small Seeds are brownish, slightly winged and 3-angled. (Feb-Jul). The insect is unknown.?

: 16. 2018/03/07. Walter Sisulu NBG. Photo: David Becking.

: 981. 2014/08/05. Walter Sisulu NBG. Photo: David Becking.

Distribution and Ecology

This hardy Tree is somewhat rare and found in forests and forested ravines. They can sustain some frost and infrequent droughts. This plant is only found in Eswatini (Swaziland) and Eastern mountains of Mpumalanga e.g., Barberton. This plants is thus Endemic in southern Africa (Endemism is the ecological state of a species being unique to a defined geographic location). They grow in moist areas, in full sun and in altitudes ranging from 730-1 600m. The small flower size suggests that the agents of pollination are small insects that are attracted by the nectar. These insects, include butterflies, bees and wasps. Growth rate is about 1m per year. Young plants are sensitive to severe frost.

Ethnobotany

This is a good Garden tree prospect. It can tolerate some frost and survives infrequent droughts but not extremely dry areas. Roots are relatively trouble free. Propagation is from fresh seeds. It is moderately fast growing – about 1m per year. Plant fresh seeds in spring in a shady area–and transfer plants to a sunny location. Planting a number of these small plants to grow together is impressive – if there is sufficient space (photo 240 under Tree). This plant does well in a container. Keep plants moist in summer.