Euphobia helioscopia 澤漆

Common name: Sun Spurge
Scientific name: Euphobia helioscopia 澤漆
Genus: Euphorbia 大戟屬
Family: Euphorbiaceae 大戟科, spurge family

Remarks:

Origin: Archaeophyte (established before 1500 AD.) It has a Eurasian Southern-temperate distribution.

Date:  1st April

All flower head heading to the same direction in this arable field. Does it represent that they track the sun as it moves across the sky?

A young single plant. No leaves at the base of the stem. A mature plant can reach up to 50 cm.

Leaves (green) are alternate. The yellowish green leaves-like structure on the top of the plants are in fact bracts of the inflorescence. All bracts are similar to leaves.

The leaf (the green one in the middle of the photo) is obovate and toothed.

The underside of the flower head showing the underside of the bracts as well as the bracts). 

enalarged below

Side view of the inflorescence. The inflorescence branched 5-rayed first, then 3-rayed at the next branch.

L: leaves. Bu: bracts at the base of the 5-rayed umbel (there are totally 5 Bu but the above photo can only show parts of them). Ba:  3 bracts of the (above) upper branch that is 3-rayed this time.

It could be seen clearly that the inflorescence branched 5-rayed first, then 3-rayed.

Another plant enlarged below to see the structure of the flowers

Cm: cyathium (the condensed inflorescence in Euphorbia) at the centre (middle) of the plant. C1-C5: the 5 cyathiums outsdie the middle cyathium (Cm), developed from the 5-rayed umbel at the first branch. Each cyathium has 4 rounded glands (G), 5 male flowers and 1 female flower. Each male flower could be seen as one stamen with anthers (A) at the top of it. (Only two stamens could be seen protruding from the middle cyathium at this stage.)  Female flower with the ovary (O) and 3-rayed style (S) could be seen in the above photo just start to protrude from the cyathium.  

Another plant enlarged below

For each cyathium, the female flower is much more elongated for this flower and bends downwards.

One more plant enlarged below to see the detailed structure of the flowers.

The bottom left corner of the original photo. Enlarged further below to see the detailed structure of the flower.

The central cyathium and the three surrounding cyathiums arising from the 3-rayed branch. Dark green, round glands, stamens and female flowers could be clearly seen here.

The top section of the original photo. Enlarged further below to see the detailed structure of the flower.

The bottom section of the original photo. Enlarged further below to see the detailed structure of the flower.

The ovary (at the middle bottom of the photo) is enlarged, maybe it is fruiting now.