KNAPWEED BROOMRAPE

Orobanche elatior

Broomrape Family [Orobanchaceae]

month8jun month8june month8jul month8july

status
statusZnative
flower
flower8brown flower8cream
inner
inner8yellow
morph
morph8zygo
petals
petalsZ2
type
typeZspiked
type
typeZtubular
type
typeZfringed
stem
stem8round

2nd July 2013, Noar Hill, Hampshire. Photo: © Dawn Nelson
A stout, upright plant growing up to 75cm high with a long spike of honey-coloured (usually tinged purple) flowers. Totally lacking chlorophyll it is brownish throughout and  parasitic on Greater Knapweed (Centaurea scabiosa) only. The flowers are tubular, curving from upwards to outwards like ship ventilators.


2nd July 2013, Noar Hill, Hampshire. Photo: © Dawn Nelson
Tapering as it nears the ground this stem seems to defy the normal shape of stems.


2nd July 2013, Noar Hill, Hampshire. Photo: © Dawn Nelson
A honey-coloured yellowish-brown not dissimilar in colour to that of another saprophyte Yellow Birdsnest (Hypopitys monotropa) [was once Monotropa hypopitys!] and to that of the orchid Bird's-Nest Orchid (Neottia nidus-avis) to which it looks more similar.


2nd July 2013, Noar Hill, Hampshire. Photo: © Dawn Nelson
Here the flowers are tinged purple, as is normal. The tubular flower splays out at the opening in an untidy frilly nature; but there is order here: Although there are only 2 lips, the upper forms a frilly 2-lobed sunshade and the lower is folded into three frilly 'lobes'.
The bracts between the flowers, one per flower, are very narrow, long and brown, several can be seen. Under the hood lurks a stigma with two yellow ovaloid organs at the ends.


2nd July 2013, Noar Hill, Hampshire. Photo: © Dawn Nelson
The flower has darker veins, some branched. Very short hairs cover the flower.


Not to be semantically confused with : Broom [a plant with similar name]

Some similarities to : both Ivy Broomrape (Orobanche hederae) and Greater Broomrape (Orobanche rapum-genistae) which are a similar colour, but the former has creamier coloured flowers and is parasitic mainly on Ivy (Hedera Helix) whilst the latter is slightly taller and more butter-coloured parasitising on woody Pea flowers. The best way of differentiating between them is to observe the host plant, but that may be several metres away.

Slight resemblance to : Toothwort (Lathrae squamaria) which is also a chlorophyll-less parasitic plant and is a pale creamy pink and less than half the height at only 30cm.

Superficial resemblance to : Yellow Bird's-nest (Hypopitys monotropa) but that is also shorter at 30cm and moreover is bent over double at the end like a walking stick.

No relation to : Broom (Cytisus scoparius) or Butcher's Broom (Ruscus aculeatus) [plants with similar name belonging to differing families].

After Common Broomrape (Orobanche minor) this is the next most frequent species. Occupies only the South East of the UK.

Knapweed Broomrape totally lacks chlorophyll and cannot photosynthesis itself, it is totally dependant upon its exclusive parasitic host, Greater Knapweed (Centaurea scabiosa) for nutrition. It's host may be several metres away, connected by the underground root systems, but always on limy soils. All Broomrapes are  Parasitic Plants.


  Orobanche elatior  ⇐ Global Aspect ⇒ Orobanchaceae  

Distribution
 family8Broomrape family8Orobanchaceae

 BSBI maps
genus8Orobanche
Orobanche
(Broomrapes)

KNAPWEED BROOMRAPE

Orobanche elatior

Broomrape Family [Orobanchaceae]