Sonchus

Arable sow thistle ( Sonchus arvensis)

The geese thistles ( Sonchus ) constitute a genus in the subfamily Cichorioideae within the sunflower family ( Asteraceae). Other common names are milk thistle or Saudi fifteen digits.

  • 2.1 Types and distribution

Description

Vegetative characteristics

Sowthistle species are annual, biennial or perennial herbaceous plants, rarely are they woody at the base. The stems are usually solitary, branched and hollow. The leaves are on the edge of bristly - prickly toothed to pinnately lobed. The stem leaves are amplexicaul. All plant parts contain latex.

Generative features

In a total inflorescence there are few to numerous basket- shaped part inflorescences. The flower heads contain only ray florets. The sheath is extended bulbous at the base. The bracts are arranged in three rows in tile- like arrangement. At the bottom basket, there is no chaff leaves. The ray florets are yellow.

The achenes are pressed together, thereby narrowing at both ends without beak. The pappus has simple, rough bristles in several rows.

System

The genus Sonchus was erected in 1753 by Carl Linnaeus in Species Plantarum. As Lectotypusart oleraceus Sonchus L. 1913 Nathaniel Lord Britton determined by and Addison Brown. The genus belongs to the subtribe Sonchus Hyoseridinae from the tribe Cichorieae in the subfamily Cichorioideae within the family (Asteraceae ) Asteraceae.

Types and distribution

In Northern and Central Europe following widespread species are indigenous:

  • Arable sow thistle ( Sonchus arvensis L.)
  • Prickly Sow- thistle ( Sonchus asper (L.) Hill )
  • Vegetable sow thistle ( Sonchus oleraceus L.)
  • Marsh sowthistle ( Sonchus palustris L.)

In Southern Europe, North Africa and the Middle East following additional species occur:

  • Sonchus briquetianus Gand. It occurs only in Morocco.
  • Sonchus bulbosus (L.) Greuter & N.Kilian ( Syn: leontodon bulbosus L., Crepis bulbosa (L. ) Exchange, Aetheorhiza bulbosa (L.) Cass. ): With three subspecies: Sonchus bulbosus subsp. bulbosus: It is widespread in the Mediterranean area.
  • Sonchus bulbosus subsp. microcephalus ( Rech.f. ) N.Kilian & Greuter: It occurs in Greece, Turkey, Lebanon and Syria.
  • Sonchus bulbosus subsp. willkommii ( Burnat & Barbey ) N.Kilian & Greuter: It occurs only in the Balearic Islands.
  • Sonchus maritimus subsp. aquatilis ( Pourr. ) Nyman:
  • Sonchus maritimus L. subsp. maritimus

Especially in the Canary Islands, but also in Madeira there are many endemic Sonchus species, which are usually even shrubs. This includes the following species that only appear to the said islands:

  • Stemless sow thistle ( Sonchus acaulis Dum. -Cours. ): It occurs in Tenerife and Gran Canaria.
  • Sonchus arboreus DC. It occurs on La Palma and Tenerife.
  • Sonchus bornmuelleri pit. You occurs on La Palma.
  • Sonchus bourgeaui Sch.Bip. It occurs in Gran Canaria, Fuerteventura, Lanzarote and Morocco.
  • Sonchus brachylobus Sch.Bip. It occurs on Gran Canaria.
  • Sonchus bupleuroides ( font cross ) N.Kilian & Greuter: It occurs on Gran Canaria.
  • Canary Island Sow-thistle ( Sonchus canariensis ( Sch.Bip. ) Boulos ). The two subspecies: Sonchus canariensis ( Sch. Bip. ) Boulos subsp. canariensis: It occurs in Tenerife and Gran Canaria.
  • Sonchus canariensis subsp. orotavensis Boulos: It occurs in Tenerife.
  • Sonchus pendulus subsp. flaccidus ( Svent. ) N.Kilian & Greuter
  • Sonchus pendulus ( Webb) Sennikov subsp. pendulus
  • Sonchus ustulatus subsp. maderensis Aldridge: It occurs on Madeira, Porto Santo and the Deserted Islands.
Pappus (flower structure) Sonchus tenerrimus Agricultural Research Service
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