Striga Lour.

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Annual or perennial hemiparasitic herbs, hirsute, pilose or scabrid; stems simple or branched mainly from above middle, stiffly erect, square or terete

Morphology Leaves

Leaves opposite or subopposite, reduced to small scales at the base

Morphology Reproductive morphology Inflorescences

Inflorescence a dense or lax terminal spike or raceme

Morphology Reproductive morphology Flowers Perianth

Calyx tubular, (4–)5(–8)-lobed; lobes equal or subequal. Corolla-tube cylindrical with an acute bend; limb 2-lipped, upper lip 2-fid or emarginate, lower lip 3-lobed

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 4, 2 long and 2 short, included; anthers with 1 theca only

Morphology Reproductive morphology Flowers Gynoecium Style

Style persistent; stigma clavate

Morphology Reproductive morphology Fruits

Capsule oblong or subovoid, with loculicidal dehiscence

Morphology Reproductive morphology Seeds

Seeds dust-like, minute, with prominent ornamented ridges.

Distribution

Genus of some 50 species in the Old World tropics, well represented in Africa.

Note

In addition to the species treated here the following species known from adjacent countries may well turn up in Somalia: S. yemenica Musselman & Hepper, S. hermonthica (Del.) Benth., S. aspera (Willd.) Benth., and S. pubiflora Klotzsch. Species of Striga (witchweeds) are among the most specialized of all root-parasites and some of them cause severe damage to cultivated crops especially in semi-arid regions of Africa.

Scrophulariaceae, D. Philcox. Flora Zambesiaca 8:2. 1990

Morphology General Habit

Annual, rarely perennial, hirsute or scabrous root-parasitic herbs.

Morphology Roots

Root system greatly condensed, adventitious roots arising from subterranean scales, these fine roots terminated by small (1–2 mm. in diam.) haustoria, in some species a large (to 5 cm.) primary haustorium present.

Morphology Stem

Stems stiffly erect, green or grey, usually square in transverse section, of ten ridged.

Morphology Leaves

Leaves opposite or nearly so, sessile or subsessile, reduced to small scales near the base of the stem in most species.

Morphology Reproductive morphology Inflorescences

Inflorescence a spike, flowers in axils of leaves (bracts) or in dense heads.

Morphology Reproductive morphology Inflorescences Bracteoles

Bracts leaf-like or reduced, bracteoles 2.

Morphology Reproductive morphology Flowers Calyx

Calyx tubular, 5-lobed or with 5 (rarely 4) teeth, in some species intracostal veins occur.

Morphology Reproductive morphology Flowers Corolla

Orifice of tube small, less than 1 mm. in diam. with hairs abundant at orifice. Corolla with a narrow tube and expanded bilabiate limb. Upper lobes fused, erect, lower lobes 3, spreading.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 4, didynamous, inserted in the tube below the orifice.

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anthers unilocular, basifixed on short filaments.

Morphology Reproductive morphology Flowers Pollen

Pollen sparse, of ten sticky.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Pistil tubular with numerous minute ovules.

Morphology Reproductive morphology Flowers Gynoecium Style

Style terete, elongate, stigma bifid.

Morphology Reproductive morphology Flowers Nectaries

Nectary present at base of ovary.

Morphology Reproductive morphology Fruits

Dehiscence loculicidal. Capsule cylindric or subovoid, style usually persistent.

Morphology Reproductive morphology Seeds

Embryo small. Seeds minute (“dust seeds”) with prominent encircling ridges. Seedlings achlorophyllous, squamate. Germination hypogeal and cryptocotylar.