Lactuca dregeana DC.

Nomenclature
The Plant List Lactuca sativa L.
GRIN Taxonomy Lactuca dregeana DC.
Cichorieae Portal Lactuca sativa L.
Tropicos Lactuca dregeana DC.


Native distribution
Africa South Africa


Key features
Lettuce gene pool Primary relative
Chromosome number 2n = 18
Habitat Wet areas along seasonal streams
Life history Annual; biennial
Breeding system Autogamous
Flower colour Yellow
EURISCO (Dec. 2017) 8 accessions


Morphological description
Plant Height 50-180 cm
Rosette leaves Narrowly lanceolate and dentate to lacerate-dentate or sometimes elliptic and pinnatisect, up to 20 × 10 cm in outline. Margins spinose-ciliate, lobes recurved-falcate and linear to lanceolate with lower margins entire but upper margins dentate, terminal lobe always linear. Undivided leaves linear to narrowly lanceolate, up to 200 × 15 mm, attenuate-apiculate. Margins irregularly denticulate-apiculate, bases sagittate-auriculate, auricle lobes up to 2 cm long, apiculate, lamina glabrous or rarely pubescent, midribs finely to strongly prickly-spinulose beneath, thin-textured, glaucous
Stem Erect, solitary, robust, simple below and branching above, glabrous or sparsely retrorsely-spinulose below, pale
Stem leaves Decreasing in size above, suberect or ±appressed to stem, sessile
Inflorescence Paniculate, divaricately branched, narrowly cylindrical to ovoid in outline. Branches up to 20 cm long, bracteate, glabrous. Bracts small, suborbicular, amplexicaul, undersurface papillate
Heads On slender, bracteate stalks mostly 1-2 cm long. Involucre cylindrical and 6-8 mm long at flowering, conical and enlarging to 13-14 × 4 mm in fruit. Phyllaries papillate-verrucose, in fruit outer lanceolate ±2 mm long and inner narrowly lanceolate, ±12 mm long, margins becoming involute, reflexing completely to shed achenes. Florets 12-17 per head. Corollas pale yellow, ±9 mm long, tubes slender, ±pilose at mouth, ligules spreading, ±5 mm long
Achenes Pale yellowish-brown with paler beak ± as long as or slightly longer than body. Body oblanceolate, compressed, ±3.5-4.0 × 1.5 mm, broadly ribbed on margins and narrowly 5- or 6-ribbed on each face, hispidulous towards apex. Beak 3.0-4.5 mm long, apically expanded. Pappus several-seriate, of numerous white, barbellate bristles 4-5 mm long, free
Reference Van Herwijnen Z.O. & Manning J.C. (2017) A review of the history and taxonomy of the enigmatic southern African endemic wild lettuce Lactuca dregeana DC. (Asteraceae: Lactuceae: Lactucinae). South African Journal of Botany 108: 352-358