Mentha longifolia(L.) L. - Horse Mint
Scientific Description:
Variable, hairy perennial with musty or pungent odour. Rhizomes mainly hypogeal with squamiform leaves. Flowering stems 40−120 cm. Leaves (25−)30−90 × 10−32(−40) mm, sessile or rarely petiolate, oblong-elliptic to oblong-lanceolate, broadest at or above middle, apex ± acute, base cordate to subcordate, margin sharply serrate with many irregular and often spreading teeth. Lamina smooth or very weakly rugose, green- to grey-tomentose above, green- to white-tomentose beneath (discolorous in subsp. longifolia), sometimes minutely puberulous on both surfaces. Leaf hairs unbranched, finely matted beneath when dry, basal cell 18−36(−41) µm diam. Verticillasters many, congested, forming a terminal often much branched spike (30−)40−100 × (7−)9−15 mm diam. Calyx 1−3 mm. Corolla lilac or white. Nutlets chestnut, reticulate.
subsp. longifolia
Leaves more than 50 mm × 18 mm, discolorous with thin-walled hairs beneath, collapsing when dry; spikes robust, 12 mm diam., with usually sessile or subsessile branches.
Flowering time: June−August.
Habitat: Streamsides and marshes, 600−2300 m.
subsp. typhoides (Briq. ) Harley
Leaves usually less than 50 mm × 20 mm, concolorous with long to very short and curved, thick-walled hairs beneath, scarcely collapsing when dry; spikes more slender, to 10 mm diam., branches pedunculate.
Flowering time: July−October.
Habitat: Marshy fields, by streams and rivers, 900−2135 m.
Reference:
Harley RM (1982). Mentha longifolia (L.) Hudson, In: Davis PH (ed.), Flora of Turkey and the East Aegean Islands, Edinburgh University Press, Edinburgh, 7: 388−389.
Public Description:
Mentha longifolia, known as “horse mint”, is native to Europe, western and central Asia, and northern and southern Africa. It is a very variable herbaceous perennial plant with lilac or white flowers, and grows up to 120 cm in length. It blooms between June and October and is found in marshy fields, and by streams. Leaves and flowering branches have peppermint-scented aroma and show antispasmodic, carminative and stimulant effects. When taken in the form of the extracted essential oil, can cause abortions in pregnancy.
References:
Anonymous 1 (2016). https://en.wikipedia.org/wiki/Mentha_longifolia, Accessed date: 14.02.2016.
Anonymous 2 (2016). http://www.pfaf.org/user/Plant.aspx?LatinName=Mentha+longifolia, Accessed date: 14.02.2016.
Dirmenci T (2012). Mentha L., In: Güner, A., Aslan, S., Ekim, T., Vural, M. & Babaç, M.T. (eds.), Türkiye Bitkileri Listesi (Damarlı Bitkiler). Nezahat Gökyiğit Botanik Bahçesi ve Flora Araştırmaları Derneği Yayını. İstanbul, pp. 561–562.