''Thesium humifusum'' is a species of

hemiparasitic A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All parasitic plants develop a specialized organ called the ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the family

Santalaceae The Santalaceae, sandalwoods, are a widely distributed family of flowering plants (including small trees, shrubs, perennial herbs, and epiphytic climbersHewson & George t al.br>''Santalaceae'' taxonomy, 1984, pp. 191-194.) which, like other membe ...

found in western Europe and north-western Africa, known as bastard-toadflax.

Distribution

Within continental Europe, ''Thesium humifusum'' is found throughout

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

and

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

. In the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

, it is very rare, being now restricted to a single dune system near

Katwijk aan Zee Katwijk aan Zee (literally, ''Katwijk-upon-Sea'') is a seaside resort located on the North Sea at the mouth of the Oude Rijn. It is situated in the municipality of Katwijk and the province of South Holland. History The Origin till the Gol ...

. In

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

, it can be found in coastal dunes in Flanders, and perhaps one site in Wallonia. It is the only species of ''Thesium'' in Great Britain, and is there considered 'scarce'. ''Thesium humifusum'' may also occur in parts of

North Africa North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...

Ecology

''Thesium humifusum'' is a hemiparasitic plant that steals nutrients from hedge bedstraw (''Galium album'') or

lady's bedstraw ''Galium verum'' (lady's bedstraw or yellow bedstraw) is a herbaceous perennial plant of the family Rubiaceae. It is widespread across most of Europe, North Africa, and temperate Asia from Israel, Lebanon and Turkey to Japan and Kamchatka. It is ...

(''Galium verum''). Although it can be abundant in appropriate habitats, its low growth habit and inconspicuous flowers mean that it is often overlooked. In Great Britain, it is restricted to

downland Downland, chalkland, chalk downs or just downs are areas of open chalk hills, such as the North Downs. This term is used to describe the characteristic landscape in southern England where chalk is exposed at the surface. The name "downs" is deriv ...

s over

chalk Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Chalk ...

oolitic limestone Oolite or oölite (''egg stone'') is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Ancient Greek word for egg (ᾠόν). Strictly, oolites consist of ooids of diameter 0.25–2 ...

in southern England. Elsewhere, it may also grow in sand dune systems.

Description

''Thesium humifusum'' usually grows flat along the ground, only occasionally producing more erect flowering stems. Its leaves are a yellowish green colour and are strap-shaped and up to long, with a single central vein. The flowers are also yellowish, and only long. They have five

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s, five

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s, and a single

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...

with three ovules and one style.

Taxonomy

''Thesium humifusum'' was first described by

Augustin Pyramus de Candolle Augustin Pyramus (or Pyrame) de Candolle (, , ; 4 February 17789 September 1841) was a Swiss botanist. René Louiche Desfontaines launched de Candolle's botanical career by recommending him at a herbarium. Within a couple of years de Candol ...

in the 1815 third edition of his ''Flore Française''. In English, it is known simply as 'bastard-toadflax'.

References

External links

* * {{Taxonbar, from=Q2694221 Santalaceae Plants described in 1815