A REVIEW OF THE DIFFERENCES BETWEEN THE SUBSPECIES AND VARIETIES OF TREE SPECIES WHICH OCCUR IN ZIMBABWE  by Meg Coates Palgrave

DEFINITIONS ACCORDING to THE KEW PLANT GLOSSARY, (2010) HENK BEENTJE

Species: the Linnaean unit of plant classification denoting a group of populations of similar morphology (external appearance) and constant distinctive character thought to be able to interbreed and produce fully fertile progeny.

Subspecies (subsp.): a subdivision of a species.; each subspecies being geographically or ecologically distinct, isolated from each other and with fewer distinguishing characters than demarcate a species; often used merely in a hierarchical sense of being between a species and a variety.

Variety (var.):  a subdivision below the level of subspecies with one or several distinguishing characters, not separated geographically from other individuals of the same taxa.

For photographs and more information about any of the species below, go straight to Flora of Zimbabwe.

 

 

Acacia goetzei

subsp. goetzei

Leaflets 5 – 11 pairs per pinna, variable in size usually more than 3mm wide.

subsp. microphylla

Leaflets 8 – 23 pairs per pinna, minute usually less than 3mm wide.

Acacia hebeclada

subsp. chobiensis

Large riverine shrub, the lower branches touching the ground and often half submerged; distance between the nodes up to 4cm; pods more than 2.5cm wide.

subsp. hebeclada

Low spreading shrub to 3m; distance between the nodes up to 1.5cm; pods less that 2.5cm wide.

Acacia robusta

subsp. clavigera

Rachis velvety; pinnae 5-6 pairs; leaflets 13-15 pairs each leaflet about 2-3mm wide; pods sickle-shaped, up to 1.7cm wide.

subsp. robusta

Rachis almost without hairs; pinnae 2 – 4; leaflets about 5mm wide; pods robust, only slightly curved, up to 3cm wide.

Acacia senegal 

var. leiorhachis

A slender spindly tree with irregular straggling branches; bark with a conspicuous yellowish papery peel; pod without hairs, longish and narrow (up to 1.9cm wide), apex rounded without a “beak”.

var. rostrata

Growth shrubby, branching low with a dense flattened crown; bark with a pale flaking papery peel; inflorescence axis pubescent; pod, maybe hairy, short and broad (1,2-3,4 cm wide) with a “beak” at the apex.

Acacia sieberiana

var.  sieberiana

Leaves and twigs hairless or only sparsely hairy; branches ascending at about 45°, smooth, yellowish or orangish.

var. woodii

Leaves and twigs densely hairy; bark yellowish, flaking off in corky or papery pieces; mature trees often flat topped.

Acacia tortilis

subsp. heteracantha

Pods very twisted, almost hairless and without glands; wide distribution, not confined to riverine or flood plain habitats.

subsp. spirocarpa

Pods, less twisted, with spreading curved hairs and numerous dark red glands (x10 lens) usually occurs in riverine vegetation or on flood plains.

Bridelia cathartica

subsp. cathartica

Leaves seldom longer than 6 cm, usually about 3,5 x 1,5 cm, with up to 14 pairs of closely parallel lateral veins, low-altitude riverine fringe thicket.

subsp. melanthesoides

Leaves up to 12 cm long, with up to 10 pairs of widely spaced lateral veins, mixed open woodland at medium altitudes.

Cassia abbreviata

subsp. abbreviata

Leaves with loose hairs, sometimes curly, pods very velvety.

subsp. beareana

Leaves with very fine straight hairs pressed flat against the surface; pods smooth or only finely velvety.

Carissa bispinosa

subsp. spinosa

Spines stout, numerous up to 4.5cm long; leaves thick broadly ovate to sub-circular; hot dry areas at medium to low altitudes.

subsp. zambesiensis

Spines slender, rather delicate, no longer than 3 cm; leaves, lanceolate, ovate to elliptic; understorey in forest.

Cleistanthus schlechteri

var. pubescens

Ovary and fruit hairy.

var. schlechteri

Ovary and fruit hairless.

Combretum apiculatum

subsp. apiculatum

Mature leaves without hairs except sometimes for tufts in the axial of lateral veins or along the midrib.

subsp. leutweinii

Mature leaves with hairs.

Combretum collinum

subsp. gazense        

Leaves medium green to greyish green, with whitish hairs on one or both surfaces; pods rich rusty brown covered with dark, reddish brown scales.

subsp. ondongense 

Leaves with undersurface ­hairless, yellowish green, veins same colour as the leaf and often indistinct; pods pale reddish brown and rather pointed, often shrub-like and occurring mainly on Kalahari sand. This subspecies appears to be the only one which develops galls, which look like small woody fruits without the wings, about 2–3 x 0,5 cm, tapering to both ends and have been recorded as containing small yellow larvae.

subsp. suluense  

Leaves drooping, undersurface pale yellowish green, covered with brown scales, midrib and domatia hairy; pods red-brown, densely hairy.

subsp. taborense

Leaves with undersurface pale silvery green, densely covered with white scales; pods hairless, dark red-brown and somewhat pointed.

Combretum psidioides

subsp. dinteri

Leaves with silvery silky hairs, undersurface densely covered with hairs, margin hair-fringed, petiole densely velvety and greyish, tips of petals fringed with hairs.

subsp. glabrum

Leaves hairless below; young leaves glutinous on top; petals not fringed with hairs.

subsp. psidioides

Leaves with sparse hairs on the veins underneath; young leaves not glutinous; petals fringed with hairs leaves densely covered with hairs underneath; young leaves not glutinous; petals fringed with hairs.

Commiphora africana

var. africana

A shrub in mopane; calyx and pedicels hairless.

var. rubriflora

A tree, widespread; calyx and pedicels hairy.

Croton gratissimus

var. gratissimus

Leaves hairless on the upper surface; in a variety of habitats.

var. subgratissimus

Leaves with stellate hairs on the upper surface; sandstone.

Dichrostachys cinerea

subsp. africana

Pinnae 7-19 pairs, 1.5-4.5cm long; leaflets usually less than 6mm long and 2mm wide (2-5 x 0.7-2mm) pods 4-8mm wide.

subsp. nyassana

Pinnae 6-11 pairs, 4-8cm long on the larger leaves; leaflets more than 6mm long and 2mm wide (6-14  2-3mm) pods 4-8mm wide.

Diospyros lycioides

subsp. lycioides

Leaves with secondary veins hardly visible, usually hairless or with a few appressed hairs.

subsp. sericea

Leaves with secondary veins prominently raised, below, usually hairy, sometimes slightly sunken above.

Elephantorrhiza  goetzei

subsp. goetzei

Pinnae more than 14 pairs; leaflets 20-48 pairs.

subsp. lata

Pinnae less than 15 pairs; leaflets 9-28 pairs; leaflet width more than 3mm.

Euclea crispa

subsp. crispa

Leaves less than 7 x long as broad.

subsp. lineris

Leaves more than 7 x long a broad.

Euclea natalensis

var. acutifolia

Leaves more than 2.5cm wide.

var. angustifolia

Leaves less than 1.6 cm wide.

Euphorbia confinalis

subsp. confinalis

Single stemmed, 3 – 4 angled.

subsp. rhodesiaca

Stout stem, usually branched; 5 – 6 angled.

Euphorbia cooperi

var. calidicola

Branchlets 3 – 4 winged; wings about 3mm thick. Zambezi Valley.

var. cooperi

Branchlets 4 – 6 winged; wings 5-6m thick.

Ficus natalensis

subsp. graniticola

Sprawling rock-splitter, occurring inland among granite boulders; leaves tending to be truncate or ‘cut off’ at the apex.

subsp. natalensis

Multi-stemmed tree often festooned with aerial roots; distribution more or less coastal, also just into south eastern Zimbabwe.

Ficus sycomorus

subsp. gnaphalocarpa

Figs in ones or twos in the leaf axils, often maturing after the leaves have fallen.

subsp. sycomorus

Figs in heavy, branched masses, shortly stalked, on the trunk and main branches.

Gardenia volkensii

subsp. spatulifolia

Fruit about 6 x 3–5 cm, very shallowly ribbed, with small lenticels; widespread.

subsp. volkensii

Fruit 7–10 cm long, white, with coarse to shallow ribs and conspicuous lenticels occurring in the extreme south east.

Hexalobus monopetalus

var. monopetalus

Leaves oblong to elliptic, lateral veins and reticulate venation visible above.

var. obovatus

Leaves obovate, lateral veins usually prominent on both surfaces.

Hymenocardia acida

var. acida

Leaves often hairless below, fruits hairless.

var. mollis

Leaves with undersurface often velvety, fruits velvety.

Lannea schweinfurthii

var. stuhlmannii

Mature leaves usually more or less hairless.

var. tomentosa

Mature leaves very hairy on both surfaces, particularly the undersurface.

Maerua juncea

subsp. crustata

Flowers with broadly elliptic petals, fruit with very rough skin, resembling a small lemon.

subsp. juncea

Flowers with almost round petals, fruit with a  smooth skin.

Newtonia hildebrandtii

var. hildebrandtii

Leaflets more or less hairless or only slightly velvety.

var. pubescens

Leaflets densely velvety.

Pavetta comostyla

var. comostyla

Leaves hairless.

var. inyangensis

Leaves sparsely hairy on both sides.

Pavetta gardeniifolia

var. gardeniifolia

Young branches and leaves hairless, or if hairy only so on the midrib.

var. subtomentosa

All parts usually hairy and hairs on leaves not confined to the midrib.

Protea angolensis

var. angolensis

Suffrutex with numerous simple stems, up to 50 cm high, flowers Jan-Mar.

var. divaricata

Shrub or small tree, flowers May-Jun.

Pseudolachnostylis maprouneifolia

var. dekindtii

Leaves with under surface uniformly pubescent; male inflorescences usually without a stalk.  Kalahari sand.

var. glabra

Young shoots and leaves quite hairless; male inflorescences usually with a stalk.

var. maprouneifolia

Leaves with under surface hairy only on the midrib; male inflorescences with a stalk.

Pterocarpus rotundifolius

subsp. martinii

Leaflets 9-13, ovate, apex tapering to a point.

subsp. polyanthus

Leaflets oval to elliptic, 6-9 pairs, lateral veins not distinct on upper surface and with tawny hairs.

subsp. rotundifolius

Leaflets round, 1-3 pairs; lateral veins conspicuous on upper surface and with fine velvety hairs.

Rothmannia fischeri

subsp. fischeri

Leaves elliptic to broadly elliptic or narrowly obovate, apex rounded to tapering occasionally to a point, base tapering; corolla tube more or less funnel shaped, lobes less than 2.5cm long; calyx lobes 1-9mm long; fruit round; widespread in granite kopjes and also in mixed evergreen forest patches; woodland and rocky kopjes.

subsp. moramballas

Leaves narrowly elliptic to elliptic, apex tapering to a point, base tapering; corolla tube more or less bell-shaped, lobes more than 2.5cm long; calyx lobes very reduced, only 1-3mm long; fruit round to pear shaped; prefers wetter conditions; mixed forest and forest and woodland on sand.

Salvadora persica

var. persica

Plants without hairs.

var. pubescens

Plants hairy.

Ximenia caffra

var. caffra

Leaves remain hairy to maturity.

var. natalensis

Leaves without hairs even when young.

Ziziphus mucronata

subsp. mucronata

Leaf under surface with short soft hairs often only on the veins, or hairless.

subsp. rhodesica

Leaves with pale brown rusty hairs particularly on the under surface.

This list updates the list compiled for Tree Life TREE LIFE 109 : MARCH 1989 with the help of Flora of Zimbabwe www.zimbabweflora.co.zw

Meg Coates Palgrave

In drawing up the notes and lists of subspecies and varieties I have used the list prepared by Mr. Bob Drummond and many sources of literature including various volumes of Flora Zambeziaca, Flora of Tropical East Africa, Kew Bulletin, South African and Jeppe, Trees of Southern Africa by Keith Coates Palgrave.  My thanks to Bob Drummond, Bryan Adams, Tom Muller, Jonathan Timberlake and Kim Damstra for their help.  I really appreciated it.   Meg Coates Palgrave