''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 (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the family

Santalaceae The Santalaceae, sandalwoods, are a widely distributed family of flowering plants (including small trees, shrubs, perennial plants, perennial herbs, and epiphyte, epiphytic climbersHewson & George t al.'Santalaceae'' taxonomy, 1984, pp. 191-1 ...

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 located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

and

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

. In the

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

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

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

. In

Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...

, 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 (sometimes Northern Africa) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region. However, it is sometimes defined as stretching from the Atlantic shores of t ...

Ecology

''Thesium humifusum'' is a hemiparasitic plant that steals nutrients from

hedge bedstraw ''Galium mollugo'', common name hedge bedstraw or false baby's breath, is a herbaceous perennial plant of the family Rubiaceae. It shares the name hedge bedstraw with the related European species, '' Galium album''. Description ''Galium mollugo' ...

(''Galium album'') or

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

(''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. Ch ...

oolitic limestone Oolite or oölite () is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. Strictly, oolites consist of ooids of diameter 0.25–2 millimetres; rocks composed of ooids larger than 2 mm are called pisol ...

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 (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s, and a single

ovary The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...

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 people, Swiss botany, botanist. René Louiche Desfontaines launched de Candolle's botanical career by recommending him at a herbarium. Within a couple ...

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

References

External links

* * {{Taxonbar, from=Q2694221 humifusum Plants described in 1815 Taxa named by Augustin Pyramus de Candolle