Silphium perfoliatum

It is an erect herbaceous perennial with triangular toothed leaves, and daisy-like yellow composite flower heads in summer.

"[4] There are two varieties: Silphium perfoliatum grows in sandy moist bottom lands, floodplains, near stream beds, in or adjacent to open woodland.

The stem is stout, smooth, slightly hairy (glabrous) strongly 4-angled square, like mint plants.

[7] The flowers, which appear from midsummer to autumn (fall),[8] look very similar to sunflowers, but are a lot smaller; measuring about 2.5 cm in diameter, with golden yellow ray florets.

In the middle of the flower there are small, sterile, tubular disk florets,[6] which are structurally bisexual, but the stamens are the only fertile part, and they do not produce seeds.

[13] The ray florets have female characteristics,[7] and eventually develop to become thin brown achenes with a marginal wing utilized for wind dispersal.

[7] Silphium perfoliatum is able to establish colonies due to its central taproot system and shallow rhizomes.

[17] Its invasive potential for Mid European countries is considered low, but a spread through wind, birds and harvesting machines is possible.

One has to be especially careful when growing S. perfoliatum near moving bodies of water, so that it cannot spread and germinate on river banks like Buddleja davidii does.

[18] Due to low germination rate of 15–20% with untreated seeds S. perfoliatum is usually planted as seedling.

With an expected yield of 150 dt/ha, S. perfoliatum requires the following quantities of nutrients:[22] Other tests show that fertilization is no longer necessary from the second year onwards.

[23] Silphium perfoliatum are known to be disease and herbivory resistant, although established plants can be affected by the fungus Sclerotinia.

Crops which are very susceptible to Sclerotinia sclerotiorum and therefore should not be cultivated previous to S. perfoliatum are rape seed and sunflowers.

The University of Bayreuth does not mention any relevant fungal of bacterial infections at all in their research on the cup plant.

American goldfinches feed on the seeds of S. perfoliatum and drink the water collected by the "cups" on the stems.

However, desirable traits for biofuels tend to overlap with those of invasive species, such as high productivity, low input requirements, and wide habitat breadth [42] (Raghu et al., 2013).

The high water content at the first cutting in June is not a problem when letting the plant wilt shortly.

The long blooming period and abundance of flowers provides a rich source for bees and the cultivation of honey.

[6] The people of the Chippewas tribe used the root extract for back and chest pains, to prevent excessive menstruation, and to treat lung hemorrhage.

It can help alleviate the symptoms of fevers, dry cough, asthma, spleen illness, heart and liver disease.

Studies show that the presence of phenolic acids is responsible for the species’ antiseptic activity to stimulate generation of IgG and IgM antibodies.

A flower cluster
Macro view of flower head
distributionmap.
North American distribution of Silphium perfoliatum
Seed head and seeds – MHNT
Silphium perfoliatum Orto botanico di Pisa