Linaria alpina, sometimes called alpine toadflax, is a purple-flowered plant native to mountainous areas of southern and central Europe. It belongs to the family Plantaginaceae family. It was first described by Carl Linnaeus, and given its exact name by Philip Miller.
The generic name (Linaria) is derived from the Latin name for flax (linon). It refers to the similarity of the leaves of certain species in this genus to those of the common flax species, Linum usitatissimum. The specific epithet (alpina) indicates that the plant is of alpine origin or, in any case, inhabits mountainous regions with habitats similar to alpine altitudes.
The scientific name of the species was initially defined by Linnaeus (1707âÂÂ1778) under the basionym Antirrhinum alpinum. It was later refined to its current name by the Scottish botanist Philip Miller (1691âÂÂ1771) in the 1768 publication "Gardeners Dictionary, Edition 8. London ed. 8. n. 4."
Traditionally, the spontaneous species of the Italian flora are divided into four sections: Cymbalaria, Elatinoides, Linariastrum, and Chaenarrhinum. L. alpina is included in section Linariastrum, which is characterized by sessile leaves with pinnate venation, flowers arranged in naked terminal racemes, and corollas with the throat completely obstructed by a prominent palate.
More recent classifications have assigned the species to section Supinae. Current phylogenetic research indicates that species within the genus Linaria are distributed across six clades. L. alpina is located within the sixth clade, which, together with the fifth clade, forms a sister group representing the "core" of the genus. Furthermore, L. alpina and Linaria arenaria DC. form a sister group, although the seeds of the latter are crested rather than winged.
The family Plantaginaceae includes 12 tribes, 105 genera, and over 1,800 species. The genus Linaria belongs to the tribe Antirrhineae and is composed of nearly 200 species distributed across North America, Europe, Africa, and Asia.
Until recently, Linaria alpina was included in the Veronicaceae or Scrophulariaceae families depending on the author. Modern APG classification places it within the Plantaginaceae.
Linaria alpina is a hairless herb that can behave as an annual, biennial, or perennial. It reaches heights of 5âÂÂ15 cm (2âÂÂ6 in), though some specimens can reach up to 20 cm (8 in). Its primary biological form is a scapose hemicryptophyte (overwintering buds at ground level protected by snow or litter), but it can also present as a scapose therophyte (surviving via seed) or a rhizomatous geophyte (relying on underground rhizomes). The plant is almost always prostrate (lying flat) with only the tips ascending and possesses a thread-like, often creeping rhizome. The entire plant is glabrous (hairless) and glaucous (grey-blue/waxy).
In contrast to other members of the genus, Linaria alpina is characterized by a blue-violet or pinkish corolla, without spurs. The upper lip is deeply two-lobed and yellow-orange in color, with orange throat lobes in the center, creating a striking color contrast and making it easily recognizable most of the time. This is likely an optical signal for insects.
Three to fifteen flowers form a sparse, dense, or capitate raceme approximately 1 cm long. Individual flowers are pedunculated; the stalks are 2âÂÂ4 mm during flowering, becoming straight and accrescent (6âÂÂ12 mm) during fruiting. The flowers are hermaphroditic, zygomorphic, and tetramerous.
The fruit is a porocidal capsule (3âÂÂ5 mm), nearly twice as long as the calyx. At maturity, it opens via two apical opercula (holes). The seeds are numerous and discoid with a membranous wing (winged seeds).
Flowering period: Throughout the summer, from June to August, sometimes extending into September.
It is found in many mountain ranges in southern and central Europe ranging from Spain to Romania between 1,500 and 3,000 meters, and in valleys with altitudes of up to 4,200 meters. They inhabit the alpine and nival vegetation levels, and partially the subalpine, montane, and hilly levels.
In Spain it is found in the Sierra de Gredos, the Montes de León and the Pyrenees. There is also a record in the Valencian Country at 1,200 meters altitude in the highest part of the Alt Palància region.
In France, it is found in the Jura, in several locations in Savoie and Haute-Savoie, in the Mercantour Park (up to over 2,800 m), in the Pyrenees, and in two locations in Burgundy. It is also found in other parts of the Alps (giving it its name), notably on the peaks of Champsaur (Hautes-Alpes).
In Italy besides the Alps it is also found in the central Apennine Mountains. In Friuli, near Sagrado along the Isonzo river, these plants can grow down to the plains.
It is a common species in Austria, Liechtenstein, Switzerland and northern Slovenia.
In Germany, the species is primarily distributed throughout the Bavarian Alps. Scattered occurrences, known as *Alpenschwemmling* (alpine drifters), are found in the Alpine foothills along the Lech and Isar rivers, reaching as far as Landsberg am Lech and Munich. It is considered extinct in the southeast of Baden-Württemberg.
It also has smaller recorded occurences across the Balkans in Croatia on Paklenica national park, in Bosnia and Herzegovina's Blidinje plateau, in Montenegro, in Albania's Nikaj-Mërtur natural park and as far south as Greece.
It is also found in Romania's Piatra Craiului national park.
In Slovakia, it is washed down by the Belá River near Liptovský Hrádok. In the Czech Republic, the species does not grow naturally and it occurs occasionally in Sweden, but does not reproduce there.
In Slovakia, it is classified as a critically endangered taxon. The only original locality where it occurs today is Smutná dolina in the Western Tatras, where only a few clumps are known in difficult-to-access areas.
It is an early colonizer of newly exposed, unconsolidated glacial moraine. The typical habitat for this plant includes scree slopes (ghiaioni), limestone debris, stony ground, and ruins. The preferred substrate is calcareous (limestone) but also siliceous, with a neutral-basic pH. The soil typically has low nutritional value and must remain moist. It is a calciphilous (lime-loving) plant, it inhabits the gravelly banks of mountain streams and is often washed down to lower elevations by water; for example, it reaches Lake Constance via the deposits of the Rhine, and there are older records of its occurrence on the deposits of the Danube. It tolerates constant burial by scree material well. A single underground rhizome can have up to 60 rootless shoots that penetrate coarse scree or lie on top of fine scree.
Pollination of the flowers can only be performed by heavy insects with enough strength to open the flowers such as hymenopterans (bees and wasps), lepidopterans (butterflies and moths), or dipterans (flies). Alternatively, pollination can occur via the wind (anemophilous pollination). Because the nectar is located deep within the flower, it can only be reached by insects with a long proboscis, making it accessible primarily to bumblebees.
The seeds are often carried away by rivers, snow melt and debry flows (mures) which means they can also be found on gravel banks along mountain streams. The dispersal of seeds can also occur through the wind (anemochory). Once the seeds have fallen to the ground, they are further dispersed primarily by insects, specifically ants (myrmecochory). The seeds are light germinators, for successful growth, seeds should be covered with less than 1 cm of soil so they can receive sunlight.
It is a creeping plant that is able to stabilize debris by forming many non-rooting shoots. These shoots grow between and over the stones.
In France, this species is protected in the Burgundy region (Article 1). In Switzerland, its IUCN status is NT (Near Threatened) in the Jura; it is fully protected in the cantons of Appenzell Innerrhoden, Neuchâtel, and Vaud.
The species is divided into the following subspecies: