Scilla

''Scilla'' () is a genus of about 30 to 80 species of bulb-forming perennial herbaceous plants in the family Asparagaceae, subfamily Scilloideae. Sometimes called the squills in English, they are native to woodlands, subalpine meadows, and seashores throughout Europe, Africa and the Middle East. A few species are also naturalized in Australasia and North America. Their flowers are usually blue, but white, pink, and purple types are known; most flower in early spring, but a few are autumn-flowering. Several ''Scilla'' species are valued as ornamental garden plants.

Taxonomy

Species of ''Scilla'' have been known since classical antiquity, being described by both Greek (Theophrastus (371–287 BC) and Discorides (40–90 AD)) and Roman (Pliny (23–79 AD)) writers. Theophrastus described ''Scilla hyacinthoides'' (''skilla''), and more briefly '' S. autumnalis'' and '' S. bifolia'' in his ''Historia plantarum'', where he mentions "those of squill" (σκῐ́λλης; '' skilles''). In classical literature, ''Scilla'' was known for its medicinal properties. Later mentions include pre-Linnaen botanists such as Fuchs (1542) and Clusius (1601), who considered many closely related plants to be types of ''Hyacinthus''.

The genus ''Scilla'' has a long and complicated history in terms of its classification, circumscription and subdivision, and is not fully resolved.The genus ''Scilla'' was first formally described by Linnaeus in 1753, and hence bears his name as the botanical authority, ''Scilla'' L.. In ''Scilla'', he included a six plants previously considered as ''Hyacinthus''. For instance, he renamed Clusius' ''Hyacinthus stellatus cinerei coloris'' as ''Scilla italica'' (''Hyacinthoides italica'' in modern systems) and ''Hyacinthus stellatus peruanus'' as ''Scilla peruviana'', while Fuchs' ''Hyacinthus caeruleus mas minor'', he named ''Scilla bifolia''.

In all, Linnaeus listed eight species of ''Scilla'', from the Mediterranean area, Europe and southwest Asia, and placed the genus in the grouping ''Hexandria Monogynia'' (6 stamens, 1 pistil) within his system of sexual classification (''systema sexuale''). Since he listed ''S. maritima'' (which had previously been known as scilla officinale) first this, was considered the type species. On the basis that the seed morphology distinguished this species from all the other Linnean ''Scilla'', Steinheil reclassified it as a member of a novel genus, ''Urginea'', now submerged in ''Drimia'' as ''Drimia maritima''.

Later, De Jussieu (1789), using a natural system, the relative value of plant characteristics, rather than purely sexual ones, and a hierarchical system of ranks, grouped ''Scilla'' into a "family" which he called Asphodeli, along with ''Hyacinthus'' and ''Allium''. Jaume-Saint-Hilaire (1805), while maintaining the same affiliation, recognized three species ''S. maritima'', ''S. amoena'' and ''S. italica''. By 1853, Lindley had created a very large order, the Liliaceae, in which Scilla and related genera formed one of eleven suborders, as Scilleae. This included many genera, including ''Camassia'' and ''Ornithogalum''. Treatments of Scilla in the nineteenth century include those of Dumortier (1827), Salisbury (1796, 1866) and Baker (1873), with rather different approaches.

Historically, ''Scilla'' and related genera were placed with lily-like plants in the order Liliales, for instance as the tribe Hyacintheae of the family Liliaceae. The availability of molecular phylogenetic methods in taxonomic classification led to major realignments of several related monocot orders, particularly with the adoption of the Angiosperm Phylogeny Group system. Significantly, hyacinth-like plants including ''Scilla'' were initially placed in a separate family, the Hyacinthaceae in the order Asparagales, specifically in the very large subfamily Hyacinthoideae. Since 2009, the Hyacintheae, including ''Scilla'', have been considered as Scilloideae, a subfamily of the family Asparagaceae. There they are placed as one of about 21 genera in the subtribe Hyacinthinae within tribe Hyacintheae. The most closely related genera to ''Scilla'' were ''Muscari'' Mill. and ''Chionodoxa'' Boiss.

Subdivision

For some time, ''Chionodoxa'' had been considered a possible synonym to ''Scilla bifolia'' L. and molecular methods failed to support the existence of a separate genus, but rather its specimens appeared intermixed with those of ''Scilla''. Although there are distinguishing morphological features (e.g fused tepal bases and broadened filaments), these were considered paraphyletic, having arisen in several lines within the Hyacinthaceae. Furthermore, it was observed that ''Chionodoxa'' was capable of hybridization with ''Scilla bifolia''. It was therefore proposed that ''Chionodoxa'' be considered an obsolete genus and be submerged within ''Scilla''.

Subsequently it was proposed that the species of Scilla be split into two sections, Chionodoxa that would include those taxa previously considered to belong in the genus ''Chionodoxa'', and ''Scilla'' which would contain the remainder.

Species

The precise number of ''Scilla'' species in the genus depends on which proposals to split the genus are accepted. In addition to creating two sections, some authorities have split the genus into a number of smaller genera. For instance, particularly the Eurasian species have been moved to genera such as ''Othocallis'' Salisb., so that ''Scilla siberica'' would become ''Othocallis siberica'', leaving a much smaller genus referred to as ''Scilla'' s.s. or ''Scilla'' ''sensu'' Speta, with about 30 species. But this has not been generally accepted, leaving a much larger ''Scilla'' s.l. of about 80 species. Although the Flora of North America mentions (but does not list) 50 species, World Flora Online lists 83 species, as of May 2022. Speta's scheme (1998) created 8 separate genera, but many of these are very narrowly defined being either monotypic (single species) or oligotypic (very few species).

Etymology

Both the scientific genus name ''Scilla'' and the common word ''squill'' derive, via Middle English and French from the Latin ''scilla'' and Greek ''skilla'' words for the plants. The common name squill has been applied to a number of other similar taxa such as ''Drimia''..

Distribution and habitat

Native to woodlands, subalpine meadows, and seashores throughout Europe, especially the Mediterranean, Africa, especially South Africa, Eurasia, especially southwest Asia and the Middle East. A few species are also widely naturalized, particularly in Australia, New Zealand and North America.

Cultivation and uses

Many ''Scilla'' species, notably '' S. siberica'' and members of section ''Chionodoxa'', are grown in gardens for their attractive early spring flowers.

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{{Taxonbar, from=Q157238

Asparagaceae genera