Morphological features of seed and distribution of Cuscuta epilinum

Flax dodder (family CUSCUTACEAE Dumort.) is a dangerous specialized parasitic weed. It causes serious damage to the harvest by weakening host plants and reducing the quality of the raw materials obtained. This weed infests and affects mainly flax, but it can spread to other types of crops, and is also occasionally found on weeds.

• The parasite's main target is flax
• Seed capsule shape is compressed-spherical
• Seed type is single or double

The parasite has a very wide range and is found in most agricultural zones. Flax dodder is distributed throughout the European part (almost everywhere, especially in the main flax-growing regions), in the Caucasus, Western and Eastern Siberia, the Far East, and Central Asia. Control measures begin with checking the purity of seed material.

Morphological characteristics and seed sizes

For accurate identification of the weed in a laboratory or warehouse, it is necessary to evaluate the shape of the seeds. They are formed in compressed-spherical capsules and can develop either singly or in pairs. Depending on this, seeds are divided into two types:

• Single seeds. They have an angular-spherical, heterogeneous shape. On their ventral side, there are two flat or slightly depressed faces that form a pronounced convex rib running along the entire seed.
• Double seeds. They are distinguished by an elongated-oval shape. They are connected to each other by a characteristic constriction, and the side where the seam runs remains flat.

In all dodder seeds, a rounded depressed seed scar is clearly visible. The seed surface is matte, spongy, and pitted-rough. The color is most often yellow or yellowish-gray, darker shades are less common, and the seed scar itself is always darker than the rest of the surface.