Digitalis mariana

Digitalis mariana was first described as a new species by the Swiss botanist Pierre Edmond Boissier in 1841.[1][7] Although the Flora Ibérica (2009) and the Plants of the World Online website (2017) consider it to be a valid, independent species,[4][6] the Flora Europaea (1976)[8] and the Euro+Med Plantbase (2011) considered it to be two subspecies of Digitalis purpurea: subspecies mariana,[5] and subspecies heywoodii.[9]

Two infraspecific taxa are accepted:[4][6][10]

• Digitalis mariana subsp. mariana Boiss.
• Digitalis mariana subsp. heywoodii (Pinto da Silva & Silva) P. A. Hinz

The two subspecies can be distinguished by their flower colour and the indumentum on their inflorescence. The nominate form has purple-pink flowers and short glandular hairs of only 0.3-0.4mm in length, heywoodii has flowers which are white, very rarely yellowish, sometimes with a pinkish line of various shades along the margin of the corolla, and the inflorescence is covered in longish, non-glandular hairs of 2-4mm.[6]

The nominate taxon is locally known in Spanish as campanitas or dedalera.[2][5] The Spanish name verdolobo has been recorded for the subspecies heywoodii.[2]

Both subspecies are primarily found in the Sierra Morena mountain ranges of the southern Iberian Peninsula, which extend from Portugal to Spain. The nominate subspecies is more predominant in the east, the other to the west.[6]

The subspecies heywoodii has been recorded in Alto Alentejo in Portugal, and in Spain in the provinces of Badajoz, Cáceres, Córdoba and Ciudad Real.[6] In Andalucía it is found in the northeast(???) of the region, on the southern flanks of the Sierra Morena, where it is uncommon.[11]

The nominate taxon has been found in Badajoz, Córdoba, Ciudad Real, Jaén and Sevilla, and perhaps also Huelva.[6] In Andalucía it is found in the northeast, on the southern flanks of the Sierra Morena, where it is uncommon.[11]

Both subspecies grow in cracks in the stone in rocky areas. The subspecies heywoodii is most often found in fissures in granite[6][11] and slate.[11] The nominate subspecies is usually found in more acidic soils, and often in rock falls, loose scree or among boulders.[6][11]

The specific phytosociological suballiance and alliance wherein both subspecies occur is called 'Rumici indurati-Dianthion lusitani', which is in the order 'Phagnalo saxatilis-Rumicetalia indurati', in the class 'Phagnalo saxatilis-Rumicetea indurati'. It is a characteristic species of this phytocoenosis. In this habitat it occurs together with these following characteristic species: Antirrhinum graniticum subsp. graniticum, Antirrhinum rupestris, Arrhenatherum fernandesii, Biscutella bilbilitana, Centaurea monticola subsp. citricolor, Centaurea pinnata, Coincya leptocarpa, Coincya longirostra, Coincya pseudoerucastrum subsp. pseudoerucastrum, Coincya rupestris, Conopodium bunioides subsp. aranii, Conopodium majus subsp. marizianum, Crepis oporinoides, Dianthus crassipes subsp. crassipes, Dianthus crassipes subsp. sereneanus, Dianthus lusitanus, Digitalis thapsi, Digitalis purpurea subsp. toletana, Erodium mouretti, Erysimum linifolium subsp. lagascae, Festuca duriotagana, Jasione sessiliflora subsp. tomentosa, Scrophularia oxyrhincha, Scrophularia sublyrata, Sedum hirsutum subsp. baeticum, Silene marizii, Silene × montistellensis and Verbascum rotundifolium subsp. castellanum.[12]

Both forms are legally protected in Extremadura, where they have the status of a 'taxon of special interest'. Digitalis heywoodii was listed as 'not threatened' in a 1984 national list of rare or endemic plants of Spain, but in 2000 it was listed as 'vulnerable' in the Lista roja de la flora vascular Española.[2] Both subspecies were included as 'vulnerable' in the Regional Red List of Andalucía of 2005.[2][11] The reason for this was that the different collection localities and populations in this region were small.[11]