Centaurea soskae subsp. albida, Kit Tan, Shuka & Wagenitz, 2018

Wagenitz, Gerhard, Bergmeier, Erwin, Gregor, Thomas, Meierott, Lenz, Shuka, Lulezim & Tan, Kit, 2018, A synopsis of the Centaurea soskae and triniifolia group (Centaurea sect. Acrolophus) in the Prespa area and Northern Pindos, Phytotaxa 348 (2), pp. 77-89 : 86-87

6. Centaurea soskae subsp. albida × C. triniifolia subsp. campylacme ( Figs. 1‒2 )

Within the large populations on the calcareous rocky cliffs at Lake Mikri Prespa were 3‒4 individuals which had the snow-white indumentum of C. soskae subsp. albida but the florets were suffused pink, suggesting introgression between C. soskae and the pink-flowered C. campylacme . No formal recognition is presently provided for these hybrids which produce well-developed, dark brown achenes similar to those of C.triniifolia subsp. campylacme but with the long pappus of C. soskae subsp. albida .

A key to the taxa revised is provided. It includes C. grisebachii (C. sect. Acrolophus ) as this species is common in the area and bears a superficial resemblance to C. triniifolia subsp. campylacme and is sometimes mistaken for it.

2. Terminal spinule equalling or shorter than lateral cilia; pappus shorter than body of achene...........................................................3 3. Pappus more than half length body of achene.................................................................................. C. triniifolia subsp. campylacme 3. Pappus less than half length body of achene ( Fig. 2h ) .................................................................................................. C. grisebachii 4. Florets pale yellow to almost white; terminal spinule of phyllary appendage shorter than lateral cilia; achenes dimorphic ..............

.......................................................................................................................................................................................... C. tomorosii 4. Florets yellow; terminal spinule equalling or longer than lateral cilia; achenes not dimorphic.........................................................5 5. Terminal spinule equalling or slightly longer than lateral cilia; pappus shorter than body of achene ............................ C. shumkana 5. Terminal spinule longer than lateral cilia; pappus equalling or slightly longer than body of achene.............................6 ( C. soskae ) 6. Basal leaves entire ...................................................................................................................................... C. soskae subsp. aetiensis 6. Basal leaves dissected, bi-pinnatipartite.............................................................................................................................................7 7. Plants not tufted; indumentum on leaves greyish-white, becoming greyish later.......................................... C. soskae subsp. soskae 7. Plants occurring in large tufts; indumentum on leaves remaining snow-white with age ............................... C. soskae subsp. albida

Figures

FIGURE 1. Capitula of Centaurea taxa: a, C. soskae subsp. soskae; b, C. s. subsp. aetiensis; c, C. s. subsp. albida; d, C. tomorosii; e, C. galicicae; f, C. soskae subsp. albida × C. triniifolia subsp. campylacme; g, C. triniifolia subsp. campylacme; h, C. t. subsp. campylacme (white form); i, C. shumkana.

FIGURE 2. Achenes of Centaurea taxa: a, C. soskae subsp. soskae; b, C. s. subsp. aetiensis; c, C. s. subsp. albida; d, C. tomorosii; e, C. galicicae; f, C. soskae subsp. albida × C. triniifolia subsp. campylacme; g, C. triniifolia subsp. campylacme; h, C. grisebachii; i, C. shumkana.