genus descriptions: SSAs

Achyranthes

L.
Source:
SSA
Description:
Erect perennial herbs, sometimes bushy or scandent, sometimes flowering in first year. Leaves opposite, entire, petiolate. Inflorescence a +/- slender, simple or branched, elongated solitary or fasciculate spike up to 0.3 m long, terminal on stem and branches, flowers at first congested and +/- patent, finally usually laxer and deflexed; bracts deltoid, ovate or acuminate, midrib excurrent in a spine, deflexed in fruit, persistent. Flowers bisexual, solitary in axils of bracts; bracteoles 2, spinous-aristate with excurrent midrib, lamina forming short and free to longer and adnate membranous wings; entire flower with bracteoles falling with ripening of seed. Tepals 4 or 5, 1-3(-5)-nerved, narrowly lanceolate, acuminate, mucronate with excurrent midrib, indurated in fruit especially at base. Stamens 2-5; filaments filiform, monadelphous at base, alternating with usually fringed pseudostaminodes; anthers 2-thecous. Ovary turbinate or obovoid; ovule solitary from apex of an elongated basal funicle; style cylindrical, variable in length; stigma capitellate. Capsule thin-walled, indehiscent. Seed cylindrical; perisperm/endosperm copious. x= 7 (aneuploids, high polyploidy ).
Distribution:
Species 6-8, warm temperate and tropical regions of the Old World; 1 in sthn Afr.: Achyranthes aspera L. with 3 varieties, widespread and very variable in robustness.

Mon, 2009-04-27 09:15 -- Emily Smith
Achyropsis

(Moq.) Hook.f.
Source:
SSA
Synonym(s):
Achyranthes L. sect. Achyropsis Moq.: 310 (1849).
Description:
Annual or perennial herbs or subshrubs, trichotomously branched. Leaves opposite or fascicled, entire, sessile or shortly petiolate. Inflorescences subcapitate to spicate, terminal on stem and branches, bracteate; bracts persistent, finally weakly deflexed or deflexed-ascending. Flowers bisexual, small, solitary in axils of bracts, modified sterile flowers 0; bracteoles 2, closely appressed to tepals; bracteoles and perianth falling together with fruit. Tepals 4 or 5, glabrous or pubescent, shiny, firm, deeply concave and often cucullate above, 1-3-nerved, with midrib not or scarcely excurrent in a minute mucro. Stamens 4 or 5; filaments delicate, shortly monadelphous at base, alternating with small simple or fringed pseudostaminodes; anthers 2-thecous. Ovary ovoid, glabrous; ovule solitary, suspended from a long, basal funicle; style cylindrical, very short to slender; stigma capitellate. Capsule thin-walled, indehiscent, enclosed in base of perianth. Seed ovoid or lenticular; perisperm/endosperm copious.
Distribution:
Species 6, tropical and sthn Afr.; 2 in sthn Afr., Botswana, the northern provinces, Swaziland to KwaZulu-Natal and Eastern Cape.

Mon, 2009-04-27 09:15 -- Emily Smith
Aerva

Forssk.
Source:
SSA
Synonym(s):
Ouret Adans.: 268, 586 (1763).
Description:
Perennial herbs (sometimes flowering in first year), prostrate to erect or scandent. Leaves opposite or alternate, entire, flat. Inflorescences axillary and terminal, sessile or pedunculate, woolly spikes, or spikes arranged in a loose panicle, bracteate. Flowers unisexual or bisexual, plants probably sometimes polygamous, solitary in axils of bracts; bracteoles 2; bracteoles and perianth falling together with fruit but bracts and bracteoles persistent. Tepals 5, free, oval, or lanceolate-oblong, sometimes unequal, some or all softly woolly, with membranous margin and a thin to wider green centre. Stamens (and subulate staminodes of female flowers) 5; filaments connate at base into a basin or cup, alternating with subulate to oblong pseudostaminodes; anthers 2-thecous. Ovary small; ovule solitary, suspended from an elongated basal funicle; style shorter or longer than ovary; stigmas 2 or capitellate. Capsule thin-wall, delicate, bursting irregularly, membranous, enclosed in perianth. Seed compressed-reniform, firm, black. x= 7, 8, 9, 10, 11 (polyploidy) .
Distribution:
Species +/- 10, warmer parts of Africa and Asia; 3 in sthn Afr., widespread, but absent from KwaZulu-Natal and southern Cape region.

Mon, 2009-04-27 09:15 -- Emily Smith
Alternanthera

Forssk.
Source:
SSA
Synonym(s):
Telanthera Moq.: 362 (1849); Hooker: 38 (1880); Henderson & Anderson: 104 (1966).
Description:
Annual or perennial herbs, sometimes becoming woody at base, prostrate or erect to floating or scrambling. Leaves opposite, entire. Inflorescences heads or short spikes, axillary, sessile or pedunculate, solitary or fasciculate, bracteate; bracts persistent. Flowers bisexual, solitary in axils of bracts; bracteoles 2, usually shorter than perianth, persistent or not; perianth falling with fruit. Tepals 4 or 5, free or concrescent at base, similar to very dissimilar, glabrous or furnished with smooth or denticulate hairs. Stamens 2-5, some occasionally anantherous, hypogynous; filaments monadelphous at base into a cup or tube, alternating with large and laciniate to small pseudostaminodes or these rarely obsolete; anthers 1-thecous. Ovary suborbicular or obovate in outline, usually compressed; ovule solitary, pendulous, basal; style short or absent; stigma capitellate. Capsule thin-walled or sometimes corky, indehiscent. Seeds +/- lenticular. x= 17 (7, 8, 9, 10) (high polyploidy) .
Distribution:
Species +/- 100, best represented in the New World tropics and subtropics; 4 introduced into sthn Afr., naturalised, widespread.

Mon, 2009-04-27 09:15 -- Emily Smith
Amaranthus

L.
Source:
SSA
Description:
Annual or rarely perennial herbs, erect or decumbent, glabrous or furnished with short and gland-like or multicellular hairs; plants monoecious or dioecious. Leaves alternate, simple, entire or sinuate, long-petiolate. Inflorescences basically cymose, of dense to lax axillary thyrses or upper clusters dense, leafless, aggregated and spike-like, bracteate. Flowers unisexual or bisexual; bracteoles 2-5, small and herbaceous or membranous and spinescent. Tepals (1-3)5, glabrous, membranous, equal or subequal, free or connate below and somewhat indurate, occasionally absent in flowers of dioecious spp. Stamens as many as tepals; filaments free at base; pseudostaminodes absent; anthers 2-thecous. Ovary ellipsoid, compressed; ovule solitary, subsessile, erect; style short or absent; stigmas 2 or 3, subulate or filiform. Fruit a dry capsule, usually enclosed in perianth, indehiscent or circumscissile, sometimes 2- or 3-toothed at apex. Seed globose or compressed, black, smooth and shiny; testa thin; embryo annular; endosperm present. x= 17, 8 (7, 9, 10, 12) (high polyploidy) .
Distribution:
Species +/- 60, tropical and warm temperate regions of both Old and New World, sporadic as weeds in cooler temperate areas; 15 native and introduced in sthn Afr., mostly widespread weeds of cultivation. A difficult genus, complicated by the cultivation of some species (e.g. A. lividus L. and A. tricolor L.) as green vegetables and others (especially A. caudatus L. and A. hybridus L. agg.) as grain crops. It is also a genus prone to hybridisation, though probably the frequency of natural hybrids has been overestimated.

Mon, 2009-04-27 09:15 -- Emily Smith
Arthraerua

(Kuntze) Schinz
Source:
SSA
Synonym(s):
Aerua Juss. sect. Arthraerua Kuntze: 272 (1886).
Description:
Low rounded semisucculent subshrubs, repeatedly branched; branches articulate, becoming striate. Leaves opposite, scale-like. Inflorescences small, dense, terminal, woolly spikes, bracteate. Flowers bisexual, solitary in axils of bracts. Tepals 5, free, 1-nerved, acuminate, scarious, silky. Stamens 5, free; quadrate pseudostaminodes fused to filaments; anthers 2-thecous, divergent at base. Ovary glabrous; ovules solitary on a basal funicle; style slender; stigma capitate. Capsule indehiscent, falling early with perianth.
Distribution:
Monotypic: Arthraerua leubnitziae (Kuntze) Schinz, confined to the west coast of Namibia.

Mon, 2009-04-27 09:15 -- Emily Smith
Calicorema

Hook.f.
Source:
SSA
Description:
Small, much-branched subshrubs, rigid and twiggy; young branches very shortly woolly. Leaves alternate or occasionally opposite, sometimes much reduced, fleshy. Inflorescences short to subcapitate spikes, bracteate. Flowers bisexual, solitary in axils of bracts; bracteoles 2. Tepals 5, free, stiffly membranous, subequal, with straight, silky hairs on back. Stamens 5; filaments fused to the quadrate to deltoid, fringed or entire pseudostaminodes; anthers 2-thecous. Ovary ovoid or turbinate, glabrous or downy; ovule solitary, suspended from an elongated basal funicle; style slender; stigma capitate. Capsule thin-walled, indehiscent.
Distribution:
Species 2, confined to sthn Afr., both in Namibia and Northern Cape.

Mon, 2009-04-27 09:15 -- Emily Smith
Celosia

L.
Source:
SSA
Description:
Annual or perennial herbs, sometimes rather woody at base, occasionally scandent. Leaves alternate, simple, entire or lobed. Inflorescences dense, terminal and axillary spikes, or in fascicles along floriferous branchlets, or more generally lax or compact terminal and axillary thyrses, bracteate. Flowers bisexual, small, white, silvery or rosy, sessile or shortly pedicellate; bracteoles 2. Tepals 5, free, all +/- equal, glabrous or rarely somewhat pilose. Stamens 5; filaments expanded and fused into a cup below, free portions deltoid below and narrow above or +/- swollen below; pseudostaminodes 0, rarely with minute, blunt intermediate teeth; anthers 2-thecous. Ovary ovoid to subglobose; ovules few to many, rarely solitary; style distinct and elongate to almost obsolete; stigmas 2 or 3, circular to filiform. Capsule membranous, circumscissile, sometimes thickened at apex. Seeds black, usually strongly compressed and shining, subcircular, reticulate, grooved, punctate or tuberculate, not arillate; endosperm present. x= 9 (7, 11) (high polyploidy) .
Distribution:
Species +/- 45, warmer regions of both Old and New World; 2 in sthn Afr., mainly in Namibia, Botswana, Northern Province, Mpumalanga, Swaziland, KwaZulu-Natal and Eastern Cape.

Mon, 2009-04-27 09:15 -- Emily Smith
Centema

Hook.f.
Source:
SSA
Description:
Erect perennial herbs or subshrubs; stems sometimes tuberculate. Leaves opposite, entire. Inflorescences pedunculate or sessile spike-like bracteate thyrses, each bract with a partial inflorescence of 1 or 2 bisexual flowers and 2 or 3 modified sterile flowers consisting of single very rapidly developing spines, partial inflorescence falling as a 2- or 3-spined burr. Tepals 5, inner becoming narrower, outer several-nerved, hardened at base, woolly on back. Stamens 5, unequal; filaments filiform, flattened, connate at extreme base; pseudostaminodes 0; anthers narrow, 2-thecous. Ovary +/- compressed, glabrous; ovule solitary, basal; style slender, with 2 short or elongated stigma branches. Capsule scarcely compressed, delicate except for a small firm area about base of style, irregularly ruptured by developing seed, thin-walled, indehiscent. Seed +/- horseshoe-shaped; perisperm/endosperm copious.
Distribution:
Species 2, southern tropical Africa; 1 in sthn Afr.: Centema subfusca (Moq.) Lopr., Northern Province, Swaziland and KwaZulu-Natal.

Mon, 2009-04-27 09:15 -- Emily Smith
Anacardium

L.
Source:
SSA
Description:
Trees or shrubs, polygamo-dioecious. Leaves alternate, simple, entire, coriaceous. Flowers in corymbose terminal panicles. Sepals 5, imbricate, slightly connate at base. Petals 5, imbricate, reflexed, caducous. Stamens 7-10, 1 or 2 fertile, rest sterile, unequal; filaments connate at base. Disc 0. Ovary 1-carpous, 1-locular; ovule single, ascendent; style 1 with capitate stigma. Fruit obliquely reniform on swollen pedicel. Seeds reniform with 2 large, white, thick cotyledons. x = 10, 12 or 6 ( polyploidy).
Distribution:
Species 8 in tropical America; * Anacardium occidentale L., Cashew Nut, a strong-growing, spreading tree, is becoming naturalised in parts of subtropical KwaZulu-Natal.

Mon, 2009-04-27 09:15 -- Emily Smith

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