Tourneuxia Coss., Bull. Soc. Bot. France 6: 395. 1859.

Zaika, Maxim A., Kilian, Norbert, Jones, Katy, Krinitsina, Anastasiya A., Nilova, Maya V., Speranskaya, Anna S. & Sukhorukov, Alexander P., 2020, Scorzonera sensu lato (Asteraceae, Cichorieae) - taxonomic reassessment in the light of new molecular phylogenetic and carpological analyses, PhytoKeys 137, pp. 1-85: 1

publication ID

http://dx.doi.org/10.3897/phytokeys.137.46544

persistent identifier

http://treatment.plazi.org/id/A66D92E0-BFBC-55C2-889F-68AF61A0C6EE

treatment provided by

PhytoKeys by Pensoft

scientific name

Tourneuxia Coss., Bull. Soc. Bot. France 6: 395. 1859.
status

 

Tourneuxia Coss., Bull. Soc. Bot. France 6: 395. 1859.  

Type species.

Tourneuxia variifolia   Coss.

Diagnostic features.

Subacaulescent annual; capitula solitary; pollen with 9 lacunae; receptacle convex; achenes winged; pappus in marginal achenes obliquely inserted.

Description.

Habit, life form, subterranean parts: annual subaculescent herb with taproot.

Leaves: ± rosulate, linear to spatulate, entire to pinnatifid.

Stem, synflorescence: with one to several short weak and pubescent stems, each with solitary capitulum.

Capitula: involucre tomentose, phyllaries biseriate, linear or lanceolate, equal in size; receptacle convex; capitula with > 12 florets, yellow, dorsally sometimes tinged purple, much exceeding the involucre.

Pollen: echinolophate, tricolporate and each colpus divided into 2 lacunae, with 9 (6 abporal and 3 equatorial) lacunae ( Blackmore 1982).

Achenes: 3-6 mm, compressed, smooth, with two ribs elongated into small wings, without carpopodium; achene wall with continuous sclerenchymatous layer, of parallel orientation, sometimes the fibres of the sclerenchyma are slightly obliquely orientated in the region of the wings, parenchyma subepidermal, almost continuous, more prominent in the winged areas and much thinner (1-3 layers) between them, of thin-walled cells only, air cavities absent, tannins absent.

Pappus: 4-7 mm, obliquely inserted in the marginal achenes, bristles plumose almost entirely, but scabrid in upper portion, the fimbriae of which are soft and tangled with each other, proximally brownish, distally dirty white.

Chromosome number.

x = 7, diploid.

Species.

(1) T. variifolia   Coss. - Fig. 15A, B View Figure 15

Distribution area.

N Africa (DZ; LY; MA; TN).