Dienstag, 15. Oktober 2013

Plants of the Day (October 16th, 2013) - Chenopodium album L. and Chenopodium glaucum L. (aka Oxybasis glaucum (L.) S. Fuentes, Uotila & Borsch.)


After a longer break, it's time for a new Posting. Today, I want to show you two species at once, because both plants are very similar for laymen. This species are Chenopodium glaucum L. and Chenopodium album L. Both species are member of the Amaranthaceae.

C. album - habitus

In German, the first species is known as “Graugrüner Gänsefuß” and the second species as “Weißer Gänsefuß” or “Ackermelde”. The common English name of C. glaucum is “Oak-leafed goosefoot” while C. album is known as “White Goosefoot”, “Melde” or “pigweed”.

1) Description

Both species are annual herbs. C. glaucum is highly variable in its length, which can be between 5 and (rarely) 120 centimeters (usually around 40 centimeters). However, the stalk doesn't grow straight upright but creeps over the ground, so the plant isn't very high. C. album grows upright and as a result, the species reaches heights between 15 and 180 centimeters but a maximum height over 250 centimeters is also possible. The stalk is stripped green but becomes red during autumn. The whole plant is covered with a floury white fluff, which gives it a white to greyish color. This is also the reason for the name C. album (“album” means “white”). The stalk of C. glaucum hasn't such distinctive features.

C. album - leaves and the stalk

The leaves of C. glaucum are oak-shaped with a deeply lobbed or serrated margin. Their ventral site is floury white, while the dorsal site is blueish green, what is the reason for the name of the species (“Glaucum” means “blueish”). Another distinctive feature is the white leaf-vein on the dorsal site. The leaves are also a little bit fleshy.

you can see some distinctive features of C. glaucumon this picture
(e. g. the leaf vein, the blueish green dorsal site, the white ventral
site and the creeping habitus)

The leaves of C. glaucum are highly variable in form and shape. They can be egg-shaped, laceolate or even rhomboid. This may vary from plant to plant. The same applies for the margin, which can be lobbed, roughly serrated or even smooth. However, the bracts are more narrow and often has a smooth margin.

C. album - inflorescene; you can also see the narrow
bracts

In both cases, the inflorescences are panicles, but the panicles of C. glaucum is larger and more pyramidal. Both species have very inconspicuous flowers with small, green to greyish petals and sepals. Wind is the primary pollinator and distributor, what is also a reason for this small flowers (they don't need large flowers to attract pollinators like bees or flies). Flowering time is between June and October.

2) Distribution

Both species are native to the norther hemisphere and can be found in Eurasia and North America (here as a Neophyte). The true origin of both species is unknown, but botanists believe, that both species are native to Asia, where they spread out to Europe as Archaeophytes in Accident times. From Europe, seeds of both species came to North America with ships.

C. album - stalk; you can see the stripes and the
red color of older parts.

C. glaucum and C. album are typical pioneers on ruderal wastelands and similar places. They aren't very demanding and can grow on many soils, which are unfavorable to other plants. Plant societies with species of the Genus Chenopodium are typical for rough grounds, ruderal wastelands and dumps.

Please note: current researches found out, that C. glaucum doesn't belong to the Genus Chenopodium. Today, it belongs to the Genus Oxbyasis and is known as Oxybasis glaucum (L.) S. Fuentes, Uotila & Borsch. However, I will use the old nomenclature, because it's more widespread in the literature.

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