Prospero autumnale (L.) Speta, 1982
Syn.: Scilla autumnale L.
Common names: Autumn Squill [En], Scille d’automne [Fr], Herbst-Blaustern [De], Scilla autunnale [It]
Samos ● Greece
Description: This autumnal flowering plant is a miniature lily, like a tiny Bluebell, except that the flowers do not all hang downwards. Bulb 15-20mm in diameter, ovoid. Stems 5-20cm, minutely rough towards the base, up to twice as long as the mature leaves. Leaves 5-10 (absent or very short at flowering), 4-15cm × 1-2mm, usually erect (occasionally up to 4mm wide and more or less prostrate), narrowly linear and chanelled or subfiliform, hairless. Inflorescence an elongating 6- to 20-flowered raceme; pedicels 8-15mm, ascending. Perianth segments 3-5mm, pinkish-blue to lilac. Seeds 2 by 1mm, ellipsoid, black, finely rugulose.
Widespread in the Mediterranean area, this autumn flowering species looks similar wherever it is found, be it in Greece, Turkey or Spain. However, a closer look at the cellular level reveals that the obvious morphological uniformity strongly contrasts with an extraordinarily high variability concerning chromosome number and structure.
Biology: Autumn squill is exceptional in many ways. Not only do populations often differ in their chromosome numbers (usually multiples of the chromosome base numbers of five, six or seven), but virtually every type of known chromosomal mutation has been reported from this plant. Furthermore, polyploidy - the presence of more than the normal two chromosome sets -- is frequently observed in Prospero autumnale. A change in the genomic constitution after polyploidization provokes a major challenge for the fine-tuned functioning of a cell. As a by-product of such changes, populations may become reproductively isolated, which is the hallmark of speciation.
Habitat: Dry grasslands.
Distribution: From southern England to the Caspian Sea, from Morocco to the northern Iraq.
Article about the Dr. Hanna Schneeweiss Project, Department of Systematic and Evolutionary Botany, Origin and genome evolution of chromosomal races in the polyploidy complex of Prospero autumnale, 2009.
The University of Reading Herbarium