General Info.

This Tree is up to 12m+ high and has a watery latex.  Leaves are simple, ovate and alternatively arranged.  The small, monoecious and regular Flowers are in racemes.  Fruit is a 3-lobed capsule with a persistent calyx.

Description

Croton sylvaticus

RSA Tree No. 330.

Common names: Fever Tree, Forest Fever Tree, Forest Croton.

Family: Euphorbiaceae (Euphorbia family e.g. exotic poinsettia – Euphorbia pulcherrima).  This family has about 275 genera and 7 500 species.  Our local genera containing trees include Alchornea, Croton, Euphorbia, Macaranga and Spirostachys.  This family has plants that may be herbs, shrubs or trees and latex is often present.  Leaves, when not rudimentary, are usually alternate and simple with free stipules.  Inflorescences are situated terminally or axillary.  They are mostly in cymes (a broad, more or less flat-topped, determinate flower cluster, with central flowers opening first).  They may be grouped in spikes (simple indeterminate inflorescence with sessile flowers on a single unbranched stalk), thyrses (the main axis grows indeterminately, and the branches have determinate growth) or pseudanthia (inflorescences with many flowers appearing as a single flower – like a sunflower).  In Euphorbia they appear as cyathia (where they usually have 5 joined bracts outside: up to 10 brightly coloured nectar glands which may have petal-like appendages or brightly coloured bracts followed by 5 much reduced male flowers at the base of each bracteole.  In the centre is a much-reduced female flower).  Plants may be monoecious or dioecious and the regular, unisexual Flowers may or not have a perianth.  Male flowers have 1-many stamens with free filaments and stamens with up to 4 pollen sacs.  Female flowers have a superior ovary with 1-many locules – each with up to 2 ovules.  Fruit is a capsule or nut(s).  Seeds may have a caruncle (a fleshy structure attached to the seed) and may be poisonous.

Name derivation: Croton – resembling ticks – referring to the shape of the fruit.  sylvaticusgrowing in woods. There are about 11 species of the genus Croton in the RSA.

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

Tree

This medium sized (12 to 40m high) Tree has a straight trunk, which may reach 1m wide.  The tree contains a watery latex.  The pale to dark grey Bark is smooth when young with prominent leaf scars.  The Branches become rough with age. A pink colour shows through the lengthwise-striated older bark.  Young growth may have orange hairs.  Lichen (specialised fungi cultivate algae partners that manufacture food for them by photosynthesis) may be present.  It is light grey coloured in photo 628.

Leaves

This tree may be deciduous.  The simple, ovate, alternately arranged Leaves are up to 14 x 10cm.  The Blade is darkish green and slightly shiny above, and lighter below but not significantly bicoloured. Young leaves may have stellate hairs on both sides.  Mature leaves are smooth and hairless.  There are 3-7 pairs of lateral Veins.  The veins protrude and are more visible below.  The Apex is attenuate (showing a long gradual taper of base or apex) and may end in a drip-tip.  There are 3-5 veins arising from the Base, which is rounded to slightly cordate (heart shaped).  There are 2 small protruding stalked glands at the base of the Midrib – best seen on the lower surface (photo 300).  The Margin is irregularly serrated and the teeth are glandular.  The thin Petiole (leaf stalk) is up to 7cm long.  Stipules (basal appendages of the petiole) are present but fall early.  Crushed leaves smell of almonds.

Flowers

The very small, pale greenish-yellow Flowers are contained in Racemes (a simple elongated inflorescence with stalked flowers).  Flowers are monoecious (separate male and female flowers on the same plant).  A Disc (a more or less fleshy or elevated development of the receptacle) is present.  The more numerous Male flowers are alone or are the most numerous towards the end of each inflorescence.  The Stamen Filaments are inflexed in the bud but become exserted in the mature flower.  There is no Ovary present.  The Female flowers may be located at the base of the inflorescence.  These flowers lack petals and the 5-merous calyx is smaller than in the male flowers.  The superior Ovary has a single Ovule in each locule.  (Sep-Dec).

Fruit

This almost spherical, initially light green Fruit is a 3-lobed, woody Capsule (a dry fruit resulting from the maturing of a compound ovary, which usually opens at maturity by one or more lines of dehiscence) about 1,5cm wide.  Here the calyx is slightly accrescent (the calyx continues to grow after the corolla has fallen – photo 13).  The capsule is initially slightly hairy and is perched on a small stalk.  The orange mature fruit contains about 2 Seeds and a persistent 5-lobed Calyx is present.  The seeds are carunculate (have a fleshy structure attached to the seed) and are not eaten by many birds or other animals.

Distribution & Ecology

These tree occurs naturally from Port St John’s in the Eastern Cape, KwaZulu-Natal, Limpopo and Mpumalanga.  The tree is also located in Mozambique, Zimbabwe and northwards.  These plants occur in the forest or forest margins and stream banks up to an altitude of 1 700m.  Birds that are attracted to the fruit include Green Pigeons, Hornbills and Red-eyed Turtle Doves.  This is a “rain tree” caused by spittlebugs.  Butterfly larvae with large green bodies and horny heads, of the Green-veined Charaxes (Charaxes candiope) feed on the leaves as do some moth species.

Ethnobotany

Powdered Bark is used as a fish poison.  This is an attractive garden shade tree, which can be planted from seeds.  It is slow growing and young plants need protection from frost.

References

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

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

Ginn, P.J. McIlleron, W.G. Milstein, S. 1989. The Complete Book of Southern African Birds. Struik Publishers (PTY) LTD. Third impression 1991.

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.

Schmidt, S. Lotter, M. & McCleland, W. 2002. Trees and Shrubs of Mpumalanga and the Kruger National Park.

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

 

http://redlist.sanbi.org/species.php?species=583-13

http://pza.sanbi.org/croton-sylvaticus

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

http://www.plantbook.co.za/croton-sylvaticus/

http://www.worldagroforestry.org/treedb/AFTPDFS/Croton_sylvaticus.PDF

https://www.ispotnature.org/species-dictionaries/sanbi/Croton%20sylvaticus

http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=134820

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