Broomrape Allies
What are they?
These species are all members of the Orobanchaceae, the Broomrape family. In the past, many of them were thought to be in the figwort family (Scrophulariaceae), but recent genetic studies have shown them to be better placed with the broomrapes. One thing that all of these species have in common is that they are partially parasitic (often called hemiparasites) on other plants; they have green leaves that produce chlorophyll and thus provide sustenance for the plant, but they also tap into neighbouring plants via their roots to obtain nutrients. These plants - especially rattles and bartsias - can be important in grassland communities in controlling the growth rate of otherwise more vigorous grass species and are often considered to be good indicators of a balanced, species-rich plant community.
Where are they found?
Most of these species are plants of open, grassy places on heaths, commons and roadsides. The louseworts are plants of wet heaths and bogs.
Identification
Most of these species are relatively straightforward to identify from a combination of their flowers and their leaves.
Lesser Yellow Rattle Rhinanthus minor
A native annual of dry grassland on chalky and sandy soils and in wet, grassy meadows. Flowers May to July. Plants may be single or, more often, form spreading colonies in grassy places.
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Yellow Bartsia Parentucellia viscosa
An introduced annual of dry grassy places which appears most often on newly-seeded areas and is therefore presumably arriving as a seed-contaminant of the grass seed mix. Colonies are usually short-lived and do not persist for more than a few years. Flowers June to August. Plants may be single or form small colonies in grassy places. The leaves and stems are slightly sticky with glandular hairs.
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Red Bartsia Odontites vernus
A common annual of grassy places, especially along the edge of compacted, grassy lanes, tracks and walkways. Flowers June to August. Plants may be single or form small colonies in grassy places. East Anglian plants are mostly (if not all) of the later-flowering, much-branched form which is often given the subspecies name serotinus but, as with all populations of this plant, there is a lot of individual variation.
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Marsh Lousewort Pedicularis palustris
An annual or biennial of acid bogs which may never have been common in East Anglia due to lack of suitable, acidic habitats, but which has also declined over time and is now found in just a few, well-managed wetlands, especially in the northern half of the Norfolk Broads. Flowers May to August. A rather upright species with deeply and finely cut leaves. The flowers have two pairs of tiny, pointed teeth towards the tip of the upper petal tube and the calyx is slightly hairy.
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Common Lousewort Pedicularis sylvatica
A creeping perennial species of the drier margins of acid bogs which, despite its English name, is far less common than Marsh Lousewort. Flowers May to August. A rather upright species with deeply and finely cut leaves. The flowers have one pair of tiny, pointed teeth towards the tip of the upper petal tube and the calyx is not hairy.
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Common Cow-wheat Melampyrum pratense
A rare species of undeveloped land such as ancient woodland margins and green lanes, where it grows as a semiparasite on woody plants such as hazel. Rare and probably still declining, with perhaps no more than 10 locations in East Anglia. Flowers May to August. Flowers are usually cream-coloured or tinted with yellow, but may sometimes also have a purple flush.
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Crested Cow-wheat Melampyrum cristatum
A rare species which is quite literally living life on the edge in the UK, as almost all extant colonies survive on protected roadside verges in neighbouring parts of south Cambridgeshire, north-west Essex and south-west Suffolk. One tiny colony also survives in central Norfolk. Flowers June to August. The yellow-tipped flowers emerge one or two at a time from bright purple bracts.
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Field Cow-wheat Melampyrum arvense
A rare introduction in the UK which still persists in small numbers at about five sites. Probably introduced with grain from the continent, the first British record appears to be from Norfolk in 1724 but the last East Anglian record was as long ago as 1855 and it seems unlikely that it will be found in our region again, unless deliberately introduced. Flowers June to August. The combination of yellow-marked flowers and deep reddish-purple bracts can make a truly spectacular display. The photos here were taken in Gotland, Sweden, where this species is abundant on roadside verges.
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