Taxonomic and nomenclatural notes on the genera Jasonia Cass, and Chiliadenus Cass. (Compositae)

Abstract

The starting-point for this research was the critical examination of a rupestrian chamaephyte gathered in Malta, which in the more recent local floras and in Italian floras is indicated as Jasonia glutinosa (L.) DC., species distributed in Spain, France, Balearic Islands, Lampedusa, Malta, Morocco. The doubt that it was not a well identified entity arose from the examination of numerous herbarium specimens, which has revealed the existence of some remarkable differences between the Maltese plant and Franco-Iberian one. The difference concern mostly the hairiness of the plant, the stem structure, the shape of the leaves, the disposition of the capitula in the scape, the involucral bracts and the achenes. The research for a valid basionym for these species has pointed out a confuse situation as far as nomenclature is concerned, wich has been solved, only by examinig the various types. The result has been that for the Franco-Iberian species the valid basionym is represented by Inula saxatilis Lam., while for the Malta and Lampedusa species there is none at all. As far as the genus is cocerned these species cannot be included in the genus Jasonia Cass., but are to be attributed to the genus Chiliadenus Cass., which is well differentiaded from the former by the absence of ligulate florets and for the achenes covered by hairs and glands. From these investigations we have concluded that the genus Jasonia is monotypic and it is represented by J. tuberosa (L.) DC. (= Erigeron tuberosum L.), while in the genus Chiliadenus the following entities are to be included: C. saxatilis (Lam.) Brullo comb. nov. (= Inula saxatilis Lam.), C. bocconei Brullo sp. nov. (= Orsina camphorata Bertol. p.p.), C. lopadusanus Brullo sp. nov., C. montanus (Vahl) Brullo comb. nov. (= Varthemia montana [Vahl] Boiss.), C. candicans (Delile) Brullo comb, nov. (= Varthemia canaicans [Delile] Boiss.), C. iphionoides (Boiss. & Blanche) Brullo comb. nov. (= Varthemia iphionoides Boiss. & Blanche), C. rupestris (Pomel) Brullo comb. nov. (= Jasonia rupestris Pomel), C. sericeus (Batt. & Trabut) Brullo comb. nov. (= Jasonia sericea Batt. & Trabut), C. hesperius (Maire & Wilczek) Brullo comb. nov. (= Jasonia hesperia Maire & Wilczek).