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Pyramidal Bugle

Ajuga pyramidalis

  • Family: Mint Family – Lamiaceae (Labiatae)
  • Growing form: Perennial herb. Runnerless.
  • Height: 10–25 cm (4–10 in.). Stem 4-edged, very hairy all over.
  • Flower: Corolla irregular (zygomorphic), pale blue–bluish violet, 10–18 mm (0.4–0.72 in.) long, fused, bilabiate, long-tubed. Corolla upper lip very short, 2-lobed; lower lip 3-lobed. Calyx almost regular (actinomorphic), 5-lobed. Stamens 4, of which 2 long and 2 short, fused to upper part of calyx-tube, at most slightly protruding from corolla. Gynoecium composed of 2 fused carpels. Terminal inflorescence spike-like, formed of dense, axillary whorls.
  • Leaves: In basal rosette and opposite on stem, stalked–stalkless. Rosette left after flowering time. Blade elliptic–obovate, with narrow base, round-tipped, both sides densely haired, margin shallow-toothed–almost entire. Inflorescence’s subtending bracts clearly smaller than rosette leaves, becoming gradually smaller towards top, always longer than flowers, uppermost often partly purple.
  • Fruit: 4-parted schizocarp.
  • Habitat: Dry meadows, pasture and grazing land, rich meadows, forest margins, woods.
  • Flowering time: May–June.
  • Endangerment: Near threatened.

Pyramidal bugle is a western European plant, and the plants that grow in Finland are at the eastern limit of the species’ habitat. It has probably arrived during the colonisation that followed the Swedish crusades (c. 1050–1290 CE). Pyramidal bugle thrives best in light-filled forest margins, forest pastures and grazing land. The transferral of cattle to cultivated pasture or cow-sheds was the beginning of the species’ decline. It is low-growing and runnerless, and is therefore unable to hold its own for any length of time among dense grass.

Pyramidal bugle spends most of its life as a low, inconspicuous rosette. After it has gathered enough power it grows regularly 4-edged flower-stems which are further beautified by its purple upper leaves. This signal does not go unnoticed by bumblebees, which are probably the plant’s main pollinator. The seeds have an oily appendage, an elaiosome, which attracts ants on food-finding trips. The ants then transport the seeds to new habitats.

Two other bugle species grow in Finland: blue bugle (A. reptans) and upright bugle (A. genevensis). Both are cultivated ornamentals and escapes in the wild. Blue bugle can be differentiated from its close relatives by its surface runners, which can grow up to 50 cm long. Upright bugle’s leaf-blade margins are large-toothed and its stamens are a lot longer than its upper lip. All three species can cross-breed with each other.

Other species from the same genus
Other species from the same family

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