This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The flowers are yellow, borne in loose spikes on very short flower stalks, with an expanded, flattened, smooth calyx, with 4 equal teeth, pale-green, not falling. The corolla is gaping, the upper lip being helmet-shaped with a notch at the tip, the edges rolled inwards from the back, the lower lip divided halfway into 3 segments. The bracts are egg-shaped, toothed. The capsules are included in the expanded calyx, and the seeds rattle about when ripe (hence the English name).
Photo. H. Irving - Yellow Rattle (Rhhianthus Crista-Galli, L.)
Yellow Rattle is 18 in. high. The flowers open in July and August. The plant is an annual propagated by seeds.
The anthers open widely, lie close to each other, and form enclosed in the upper lip a pollen reservoir. When this is penetrated by an insect pollen falls on the bee's head. The honey lies deep in the tube near the ovary on the receptacle, and the tube mouth is narrow. The two anthers-stalks situated forward lie close together and are clothed with pointed hairs on the inner side, so that the bee cannot insert its proboscis between them at that point, but where they are smooth. The bee, pressing the filaments back, shakes the anthers and dusts itself with pollen. The hairs prevent the pollen from being scattered.
There are two forms, one large-flowered form being cross-pollinated; the other, smaller, is self-pollinated. Yellow Rattle is visited by Bombus, and short-lipped insects cannot reach the honey.
The seeds are provided with a broad wing which aids their dispersal by the wind.
Parasitic on grasses, Yellow Rattle is a clay plant, and generally indicates by its presence poor clay soil.
The fungi Ephelina radicalis, Yellow Rattle root knot, and Coleo-sporium Euphrasiae attack it.
Two moths also infest it, Emmelesia (Lygris) albulata, grass rivulet, Botys fusialis.
Rhinanthus, L., is from the Greek rhinos, nose, anthos, flower, from the shape of the upper lip of the corolla; Crista-Galli, Dodonaeus, is the Latin for crest of a cock, in allusion to the shape of the calyx.
It is called Clock, Cock-grass, Cock's-comb, Cow-wheat, Dog's Siller, Fiddle-cases, Gowk's Sixpence, (Penny, Rattle) Grass, Hen Pen, Hen's Combs, Honeysuckle, Horse Pens, Locusts, Meadow Rattle, Money, Money-grass, Pence, Henny Penny, Penny Rattle, Penny Weed, Rattle, Rattle-bags, Rattle-box, Rattle-penny, Rottle Penny, Snaffles, Yellow Rattle.
This plant is called Rattle-penny and Money from its dry calyces rattling when shaken, and the shape of its round flat capsules. Gowk's Sixpence is the name conferred also from the shape of the capsules, and Gowk's Siller because, like the fool, it is unable to conceal its wealth.
Hen Pen is of double origin, the first from the shape of the calyx, the second from the flat seeds, like pennies. Yellow Rattle was called Locusts because in N. Bucks it was supposed to have been the food of St. John the Baptist. It was dedicated to St. Peter.
Essential Specific Characters: 242. Rhinanthus Crista-Galli, L. - Stem erect, leaves lanceolate, serrate, opposite, flowers yellow, in a spike, with ovate bracts exceeding the calyx, the lobes of upper corolla-lip round.