Lactuca elgonensis

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Lactuca elgonensis

https://pictures.bgbm.org/digilib/Scaler/IIIF/Cichorieae!Lactuca_elgonensis_Bb_01.jpg/full/full/0/default.jpg

Systematics

Lactuca elgonensis is clearly distinct from the latter species by its larger capitula with 7–8 (instead of 4–5) flowers and a correspondingly larger number of inner involucral bracts, longer (and probably brighter yellow) corollas and its longer (and probably blackish) anther tubes, but is considered as conspecific with and as a mere altitudinal form of Lactuca glanduliferaby Beentje & Stebbins (2000). This kind of diagnostic features has been found valuable for species delimitation in many over cases of the tribe. L. elgonensis should thus be considered as a separate species unless contrary evidence is provided, and its distribution (probaly restricted to the alpine zone) carefully be analysed. A

Description

Perennial herbs, stems climbing, 3.5–4 mm thick, glabrous. Cauline leaves 5–9 cm long, 3–3.5 cm wide, sessile and auriculate at the base, pinnatifid, the lobes broadly deltoid, minutely ciliate-denticulate, acute or acuminate, sparsely hirsute on the veins below, the terminal lobe much larger than the lateral and narrowly triangular, acute. Synflorescence paniculiform, nodding, the branches rather stout and divaricate; peduncles bracteate. Capitula with 7–8 flowers. Involucre at anthesis 11.5–13 mm, at fruiting 13.5–14 mm; involucral bracts with narrow but conspicuous scarious margin and broadly obtuse apex; outer involucral bracts elliptical with broader base to linear-lanceolate, the innermost more than half as long as as the inner involucral bracts; inner involucral bracts 6–8, linear-lanceolate, almost equal in length. Flowers with bright yellow corolla, 18–20 mm long, tube outside apically hirsute; anther tube c. 5.5 mm long; style branches 2.8–3 mm long. Achenes (including beak) 6 mm long, brownish yellow, somewhat compressed, minutely scabridulous, with acutely alate ribs, the 2 lateral larger than the median, the median unequal 3(–4) on each face; beak rather stout 1–1.2 mm long; Pappus white, 5.8 mm long, setae stiff.

somewhat modified by N. Kilian from Stebbins in Bull. Jard. Bot. Belg. 14: 345. 1937

Distribution

Africa: KenyanativeB; UgandanativeC

Credits

Zhang J.-W. 2017: Images (4 made by Yan-Bo Li added)

Bibliography

A. Beentje H. J. & Jeffrey C. - Cichorieae in Polhill R.M. (ed.), Flora of Tropical East Africa. Compositae 1. 2000
B. Beentje H. J. & Jeffrey C. - Cichorieae in Polhill R.M. (ed.), Flora of Tropical East Africa. Compositae 1. 2000 (as Lactuca glandulifera s.l.)
C. Jeffrey in Kew Bull. 18. 1966