General Info

This evergreen Tree may reach 9m high with paired y-shaped thorns.  Milky latex is present.  Decussate Leaves: simple, leathery and hairless.  Bisexual, regular, 5-merous scented Flowers have white spreading overlapping lobes from tubular base.  Fruit is a fleshy edible berry.

Description

Carissa macrocarpa, Ardunia macrocarpa, Carissa grandiflora, Carissa grandiflora, Jasminoenerium grandiflorum.

RSA Tree No. 640.3

Common names: Big Num-num, Large Num-num, Natal plumb, Grootnoem-noem, Green carpet.

Family: Apocynaceae (Oleander or impala lily Adenium multiflorum family).  This family includes the exotic genera Oleander and Plumeria (Frangipani).  Indigenous genera containing trees include Acokanthera, Adenium, Carissa, Rauvolfia and Tabernaemontana.  Currently the family has 366 genera and in excess of 5 000 species.  In RSA, there are 90 genera and about 700 species.  All have milky or clear sap.  The simple, entire and pinnately veined Leaves are usually opposite and may have stipules situated between the petiole and the stem.  The Inflorescence is usually a cyme (a broad, more or less flat-topped, determinate flower cluster, with central flowers opening first).  The regular and bisexual Flowers are usually bracteate.  The Calyx has 4-5, usually free sepals and the 4-5 Petals are joined – at least at the base of the staminal column.  A corona (an extension) is often present either on the corolla, or on arising from the base of the staminal column.  The 4-5 Stamens are variously located and have anthers with 2 pollen sacs.  The superior to half-inferior Ovary has 2 carpels.  Fruit is various.  The often-compressed Seeds may have a tuft of silky hair at the micropylar (a small opening in the surface of an ovule, through which the pollen tube penetrates, often visible as a small pore in the ripe seed.  During germination, the seedling’s radicle – embryonic root – emerges through the micropyle) end.

Name derivation: Carissa from Corissa – the name given to an Indian species of the same genus.  It is derived from Sanskrit (primary sacred language of Hinduism).  macrocarpa – refers to the large fruit (Greek).

Conservation Status: L C. (Least Concern). 2009 (Raimondo et al.).

Name derivation: Carissa from Corissa – the name given to an Indian species of the same genus.  It is derived from Sanskrit (primary sacred language of Hinduism).  macrocarpa – large fruit (Greek).

Conservation Status: L C. (Least Concern). 2009 (Raimondo et al.).

Tree

This is a small evergreen Tree is up to 5m high and is usually about the same width.  It is often a densely twiggy, much-branched, spiny shrub.  A harmless white Latex is present (photo 409).  Branches are rough and wrinkled into longitudinal ridges and channels.  The Bark is grey, and sharp woody Spines are present.  These paired spines have the same length.  They are Y-shaped, opposite, persistent, rigid and may be red tipped.  They initially arise at the tip of a shoot are and each spine is up to 4,5cm long.  They are once or twice forked.

Leaves

This evergreen plant has leathery, hairless Leaves that are simple (has a single blade which may have incisions that are not deep enough to divide the blade into leaflets) and decussate (with opposite leaves in 4 rows up and down the stem alternating in pairs at right angles).  The leaves are broadly ovate (egg-shaped) or oval or almost round and up to 7 x 5cm.  Lateral veins are not distinct.  Leaves are shiny dark green above and lighter below.  New leaves are a copper colour (photo 895).  The Apex is tapering to rather rounded and sharply mucronate (ending abruptly with a distinct hair like tip).  The Base is square to rounded or tapering.  The Margin is entire (with a continuous margin, not in any way indented but may be hairy) and slightly rolled under.  The Petiole (leaf stalk) is up to 5mm long and grooved on top.  Axillary glands are conspicuous.

Flowers

The conspicuous white Flowers may be tinged with pink.  Flowers have a scent similar to orange blossoms.  They are actinomorphic (regular, symmetrical.  The perianth, the calyx and corolla, are divisible into 3 or more identical sectors).  The Calyx is small, 5-lobed and imbricate (having regularly arranged, overlapping edges, as roof tiles).  The Corolla is gamopetalous (united; joined petals at least at the base) and tubular.  It is up to 1,2cm long with a hairy interior.  From this tube extend 5 spreading lobes – each up to 4cm long.  The bases of the lobes are imbricate – overlapping on one side.  As a result, if a picked flower from Carissa is carefully held and blown from the top, it will rotate (photo 367).  Flowers appear at the base of the Y-shaped spines, or terminally.  They may be in small clusters.  The 5 Stamens are attached to, and alternate with the petals but do not protrude above the corolla tube.  They are epipetalous (borne on or arising from the petals or corolla).  The Filaments are short and slender and the Anthers are 4-locular and linear-oblong.  No Disc (a more or less fleshy or elevated development of the receptacle) is present.  There is a single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma) and the entire Ovary is superior.  (Jul-Nov++).  Pollination is by small beetles, hawk moths (capable hovering and of rapid movement) and other night-flying insects.  Hawk moths often have a long proboscis, which is used in nectar feeding.  It is coiled when not in use.

Fruit

The large, ovoid, fleshy Fruit is a Berry (pulpy, indehiscent fruit like a grape or tomato) that is up to 5 x 3cm.  When mature it is red and may have a white bloom (photo 438).  It contains up to 16 thin, flat and oval to irregularly shaped Seeds.  (Sep-Jan).

Distribution & Ecology

This plant is common in frost-free coastal areas including dunes and coastal forests and usually below 500m.  It thrives in salty air.  The plant is cold (to -5°C) and drought resistant. It is naturally occurring in Western Cape, Eastern Cape, KwaZulu-Natal and Mozambique (central east to Angoche and southern border with the RSA.  Monkeys eat the Fruit.

Ethnobotany

The Fruit is edible and tasty.  The red flesh is tender and very juicy.  It is rich in magnesium, vitamin C and phosphorus and makes an excellent jam.  Up to 3 tons of fruit can be harvested per hectare annually.  It grows easily grown from cuttings, which are initially slightly frost sensitive.  Seeds and cuttings can be used for propagation but the cuttings are more successful.  It is suggested that notching young branches, bending them down and leaving them for 2 months will cause them to sprout.  Thereafter the cutting is removed and planted in sand.  It should root within a month.  This plant is now grown in Miami, Florida, California, Hawaii, Bahamas, Philippines, India, East Africa and Israel.  It is valued as a protective hedge and because it tolerates both salt spray and wind.

References

Boon, R. 2010. Pooley’s Trees of eastern South Africa. Flora and Fauna Publications Trust, Durban.

Burrows, J.E., Burrows, S.M., Lotter, M.C. & Schmidt, E. 2018. Trees and Shrubs Mozambique.  Publishing Print Matters (Pty) Ltd.  Noordhoek, Cape Town.

Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of Southern Africa, edn 3. Struik, Cape Town.

Lawrence, G. H. M, 1951. Taxonomy of Vascular Plants, The Macmillan Company, New York. Tenth Printing 1965.

Palmer, E. & Pitman, N. 1972. Trees of southern Africa, Balkema, Amsterdam, Cape Town.

van Wyk, B. & van Wyk, P. 1997 Field guide to Trees of Southern Africa, Struik, Cape Town.

http://redlist.sanbi.org/species.php?species=984-7

https://en.wikipedia.org/wiki/Carissa_macrocarpa

https://hort.purdue.edu/newcrop/morton/carissa.html

http://www.plantzafrica.com/plantcd/carismac.htm

http://posa.sanbi.org/flora/browse.php?src=SP