Silphium (genus)

Silphium radula

The Silphien ( Silphium ) are a genus which belongs to the subfamily of herbaceous in the sunflower family ( Asteraceae). The home is North America.

Description

Silphium species are perennial herbaceous plants that reach heights of growth from 20 to over 250 cm. They form rhizomes and fibrous roots or taproots. The most upright and usually branched stems are pencil -shaped or square. The whorled, alternate, or almost completely opposite, basal or on the stem are arranged distributed (sometimes all of these options on a plant ) leaves remain long or wither before flowering time. They are stalked or sessile. The leaf blades are simple or once or twice pinnately divided according to the type. There are a present to three leaf veins. The leaf margins are smooth or serrated. The leaf surfaces are smooth to hairy.

Individually or in branched inflorescences total basket- like inflorescences are formed. The bell-shaped to semi-spherical flower heads have a diameter of 10 to 30 mm. The most 11-45 bracts are in two to more than four rows; the outer ones are wider, the inner smaller and narrower. The inflorescence base is flat to slightly convex. There are chaff leaves present. Each flower head contains eight to more than 35 florets in one to four rows and 20 to more than 200 florets. The female and fertile florets ( = ray florets ) are yellow or white. The functionally male florets ( = disc florets ) are also yellow or white with a much shorter than broad corolla tube that ends in five calyx teeth.

The brown to black, more or less angular achenes have only a pappus of only two bristles which pass more or less in the Achänenkanten he or missing entirely.

Systematics and distribution

The genus Silphium was published in 1753 by Carolus Linnaeus in Species Plantarum on page 919. There are already five types of lists, of which Silphium L. solidaginoides today bears the valid name Heliopsis helianthoides Sweet. The genus name Linnaeus chose with reference to the Latin plant names silphium, the silphion 's Greek name σίλφιον back, the one North African medicinal plant called in Greek antiquity, it was probably a Ferula species.

The genus Silphium today belongs to the subtribe Engelmanniinae in Tribe Heliantheae in the subfamily of herbaceous within the sunflower family ( Asteraceae).

In the genus Silphium, there are now about 12, formerly to 22 species, they were partially varieties. They are all native to the temperate areas in North America. Individual species reached Europe at the end of the 17th century and some more during the 18th century. The cup plant ( Silphium perfoliatum L. ) was used as an ornamental plant and is overgrown in some areas.

The currently valid types are:

• Silphium albiflorum A.Gray
• Silphium L. asteriscus
• Silphium compositum Michx.
• Silphium glutinosum J.R.Allison
• Silphium integrifolium Michx.
• Compass plant ( Silphium laciniatum L.)
• Silphium mohrii Small
• Cup plant or Inconsistent Silphie ( Silphium perfoliatum L.)
• Silphium radula Nutt.
• Silphium terebinthinaceum Jacq.
• Silphium wasiotense M.Medley

No longer belong to the genus:

• Silphium peristenium Raf. ⇒ Engelmannia peristenia ( Raf. ) Goodman & CALawson
• Silphium L. trilobatum ⇒ Sphagneticola trilobata (L.) Pruski

Swell

• Jennifer A. Clevinger: Silphium in Flora of North America, Volume 21, page 83: Online. (English )