Erysimum mediohispanicum
Erysimum mediohispanicum is a perennial short-lived monocarpic herb found in many montane regions of eastern Spain where it is distributed between 800–2,000 m above sea level and inhabits forests, scrublands, and shrublands. It occupies two main regions in the Iberian Peninsula, one in the north and the other in the south-east. Erysimum mediohispanicum may be treated as one of a group or complex of six closely related species, or as Erysimum nevadense subsp. mediohispanicum.
Description
Plant morphology is very plastic in this species. Reproductive plants produce one to eight reproductive stalks from 8 to 130 cm tall. Each flowering stalk can display between 5 and approx. 100 bright yellow, hermaphroditic, slightly protandrous flowers arranged in corymbous inflorescences.Seeds germinate during early spring. Seed germination is very high, usually higher than 80% in most localities. Seedlings grow for 2–4 years as vegetative rosettes. Much mortality occurs during the first summer due to the usually severe summer drought occurring in the Mediterranean environment. Surviving individuals flower during their second year, and after flowering most individuals die. However, there are a low proportion of individuals that reproduce more than once, this proportion of iteroparous individuals varying geographically.
Taxonomy
Erysimum mediohispanicum was one of a number of new Erysimum species first described by Adolf Polatschek in 1979. Six of these, including E. mediohispanicum, were considered to be closely related and were reduced to subspecies of E. nevadense in Flora Europaea, a decision explained by Peter William Ball in 1990. The six were treated as separate species making up the E. nevadense group or complex in Flora Iberica in 1993. A molecular phylogenetic study published in 2014 included four of the species, including E. mediohispanicum. The study did not support the view that the four were closely related, and authors concluded that the E. nevadense group did not have phylogenetic support.Pollination biology
Flowers have a tetradynamous androecium, with four long and two short stamens. Each flowers contain a variable number of ovules, ranging between 15 and 30 approx. Flowers have a non-fused corolla tube formed by the union of the petals and sepals. Flowers produce minute amount of nectar in four nectaries located in the base of the corolla tube, around the ovary. Corolla shape is extremely variable, ranging from radially to bilaterally symmetric even in the same population.Flowers are visited by more than one hundred species of insects belonging to the order Hymenoptera, Diptera, Coleoptera, Lepidoptera and Heteroptera. Although this crucifer is self-compatible, it needs pollen vectors to produce full seedset. In fact, plants experimentally excluded from pollinators set only 16% of the fruits set by naturally pollinated plants. Abundant pollinators are the beetles Meligethes maurus, Dasytes subaeneus, Malachius laticollis and Anthrenus sp., the solitary bees Anthophora leucophaea and Halictus simplex, and the beeflies Bombylius spp..