EN:
FAMILY: RUBIACEAE
Synonyms: Asperula paui Font Quer; Asperula cynanchica subsp. paui (Font Quer) O. Bolòs & Vigo
DISTRIBUTION: Endemic to the northwest coast of Ibiza, La Mola in Formentera, and the islets of Es Vedrà, Es Vedranell, and S’Espartar. There are also populations along the northern coast of Alicante that belong to a different subspecies (C. paui subsp. dianensis).
CONSERVATION STATUS: Legally protected under the Balearic Catalogue of Threatened Species. IUCN Category: NT (Near Threatened)
PHENOLOGY: Blooms in summer, from June to September
LIFE FORM: Hemicryptophyte
HABITAT: Rock crevices and coastal cliffs
This is a small, herbaceous, perennial plant with square-shaped stems, highly branched from the base, which can become slightly woody. The leaves are small, somewhat fleshy, linear, arranged in whorls, and emit a characteristic scent due to papillae located at the stem nodes. The flowers, also small, are white and form terminal clusters. The fruit is a mericarp containing two seeds.
It has high biogeographical value as an extremely localized endemic. Its summer blooming suggests it is a relict species, possibly predating the current Mediterranean climate, from a time when the region was warmer and more humid, with tropical characteristics. As such, the species has been restricted to occupying microhabitats in north-facing rock crevices and coastal cliffs, to mitigate the extreme dryness of this time of year. In the Botanical Garden, the plants are well preserved in semi-shaded rock gardens. The seed bank holds two batches of seeds from Formentera and one from Ibiza. The oldest batch dates from August 1, 1989, collected in Formentera, just when the seed bank was established, thirty-six years ago.
