16,00 zł – 69,00 zł
Grass semiparasite sown to fight overly expansive monocotyledonous plants. It will cope in various places – from limestone to acidic. It can tolerate many types of soil, both fertile and barren, organic and mineral. Wild, non-cultivar seeds.
Polish name: smaller borrower
Nazwa łacińska: Rhinanthus minor (Alectorolophus minor)
Family: the broomrapes Orobanchaceae (formerly the figworts Scrophulariaceae)
Status in Poland: native
The yellow rattle is a small annual plant, a grass roots semiparasite.
The root system is shallow, slightly branched, with the youngest roots equipped with suction cups (haustoria).
Aboveground shoots are characterized by a quadrangular cross-section and obliquely growing stems. Besides, they can be very different: blackish or greenish; single or branched; slightly hairy or completely bare. They reach 0.2-0.8 m in height.
The upper leaves do not resemble the lower leaves, although they are all sessile (without petioles) and serrate at the margins. The lower ones are: opposite, pure green, and lanceolate; while the upper ones: decussate, yellowish or blackish, and triangular.
Yellow rattle is distinguished by very large pectinate flowers (compared to the rest of the plant), forming in the axils of the upper leaves. The calyx is durable, with fused sepals, very golden, strongly distended, although shorter than the corolla’s tube. The corolla is also bright yellow, with fused petals, and bilabiate. The upper lip is characterized by some flattening, the upper vault, and two purple teeth protecting the anthers underneath. The lobes of this species stick to each other, closing the torus of the flower.
The fruit is a large, light-beige capsule, covered with strongly overgrown remains of the calyx, which rustle when poked. The seeds are inconspicuous, covered with membranes that facilitate their dispersal by the wind.
Yellow rattle prefers light places, where potential hosts will grow with it. It is not picky about soils, grows poorly in limestone and best in acidic, but tolerates many types of soil, both fertile and sterile, organic and mineral. Requires stratification in frozen ground, therefore a yellow rattle is recommended for winter sowing.
For about 20 years, it has been consciously sown to limit the development of expansive grasses and dicotyledonous perennials as part of the active protection of Nardus grasslands (grassland with a predominance of nard turf) and as the component of urban flower meadows and flower margins in orchards. The yellow rattle can grow without hosts for some time, but it needs them to be fully and properly developed. It can attack over 50 species belonging to 18 families, most often grasses (Poaceae, about 30% of the most common hosts) and small-seed legumes (about 22% of good hosts).
We call the yellow rattle a “semiparasite” similarly to the mistletoe because it produces sugar on its own from carbon dioxide in the air, using the energy of light. However, it does not draw water and mineral salts from the soil like normal plants, but “steals” them from the roots of neighboring, fully self-nourishing host plants. As the haustoria of the yellow rattle are hidden in the depths of the ground it is a root semiparasite (and not a shoot one like mistletoe that develops in the host’s crown).
In rural areas, the yellow rattle is treated as a particularly harmful weed of hay meadows, pastures, and winter cereals. In permanent grasslands it was highly undesirable due to its poisonous properties to cattle and horses. The vascular plants accompanying it, it weakened not only by competing with them, but also by growing into their underground organs with his suction cups. Fighting it in the XIXth and XXth centuries was an unrewarding task, as it evolved rapidly and adapted to the terms of the hay mowing so that it always self-sown just before the swath. Due to its rapid evolution, scientists are still arguing whether the forms of yellow rattle blooming at different times of the year and attacking different species of host plants are still only ecotypes or already separate species. Despite many efforts to avoid spreading it with seeds of forage plants or with soil, the yellow rattle found its way to Canada, the USA, and New Zealand. It is also considered an alien species in the Scandinavian countries.
The best pollinators of the yellow rattle are insects with the longest mouth organs, able to drink nectar hidden at the torus of a highly elongated flower tube, e.g. hawk moths. The pistil then protrudes beyond the upper lip, acquires foreign pollen, which leads to the formation of seeds.
Although bees and bumblebees also have relatively long hypopharynxes, they usually can’t go that deep. So they rob nectar without pollinating the yellow rattle, biting holes in the sides of the corolla.