Petrosedum

x luteolum Chaboiss. ex Grulich, 1984

Parentage : P. rupestre ssp. rupestre x P. sediforme

 

Distribution : France (dep. Vienne, dep. Hautes-Pyrénées, dep. Hautes Alpes, dep. Basses Alpes, French Riviera near Gicaro), Italy (Capri).

 

 

Description (by ‘t Hart, 1978) :

 

Non-flowering shoots are indistinguishable from P. ochroleucum, P. montanum, P. rupestre and P. sediforme.

 

Flowering shoots simple, up to 60 cm long, with less crowded somewhat larger semiterete leaves.

 

Inflorescence a corymb with 3 – 8 branches, bent or slightly drooping and globose in bud, erect and concave in flower and fruit.

 

Flowers 5 – 7-merous, with bracts in the centre of the inflorescence only, sepals glabrous or with a few glandular hairs, triangular, 3 ( 2 – 4) mm long, acute to acuminate, petals pale yellow , lanceolate-elliptic, 7 – 8 mm long, somewhat cucullate, patent during anthesis, filaments pale yellow, sometimes petaloid, densely papillate at the base, carpels dark brown in fruit, seeds elongate, dark brown to black.

 

Cytology : Chromosome numbers found by ‘t Hart : 2n = 80, 2n = 96 and 2n = 120

 

Note :
P. x luteolum is a very variable taxon. Even the differential characters like the position of the inflorescence in bud, the number of bracts and the colour of the petals vary greatly. However, it is always intermediate between the supposed parental taxa, P. rupestre ssp. rupestre and P. sediforme.

 

See also : Petrosedum x luteolum : Semis spontanné en rocaille, par Éric Barbier

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