Plantago L.
(excl. Littorella Bergius)
As currently understood, Plantago consists of ca. 200 or more annual and perennial herbs and subshrubs with a world-wide distribution. It was considered monophyletic by Rahn (1996) and this was confirmed in subsequent studies (e.g. Rønsted & al. 2002). Their phylogenetic analysis identified five major clades, corresponding to the taxonomic groups Plantago subgenera Plantago, Coronopus, Psyllium, Littorella and Bougueria, all but the latter being represented in Belgium. The placement of Littorella, however, is debated. Molecular data showed it as a strongly supported monophyletic clade sister to all the other species of Plantago (Rønsted & al. l.c.). Pilger (1937) considered Littorella to be a separate genus, whereas Rahn (1996) included Littorella as a subgenus of Plantago. Chemical investigations support the latter option (Andrzejewska-Golec 1999) and its recognition at the genus level is ambiguous from a cladistic point of view (Albach & al. 2004). However, compared with the remainder of Plantago, Littorella comprises stoloniferous, aquatic plants with monoecious flowers and is fairly distinct from a morphological point of view. According to molecular data presented by Hoggard & al. (2003) its recognition at the generic rank appears warranted. Recent western European floras also treat Littorella in a conservative way (e.g. Stace 2010, Tison & de Foucault 2014) and this taxonomy is followed here as well. In Belgium Plantago is represented by five or six native species: P. coronopus L., P. lanceolata L., P. major L. (incl. P. intermedia Gilib.), P. maritima L. and P. media L. (Lambinon & Verloove 2012). Several additional species have been recorded as aliens. Claims of Plantago altissima L. turned out to be in error for P. lanceolata (Verloove & al. 2014). A recent comprehensive monograph of Plantago is lacking (Pilger 1937 being the latest monographer of the genus) but Rahn published useful accounts that deal with several sections and series (see below).
A preliminary monograph of the genus is made available by Shipunov (2018).
1 Leaves opposite on branched stems, always linear === 2
Leaves all in basal rosettes, linear to ovate === 4
2 Dwarf shrub, perennial === Plantago sempervirens
Herbaceous annual === 3
3 Floral bracts all identical in shape, ovate lanceolate, without lateral veins. Inflorescence densely glandular === Plantago afra
Floral bracts dissimilar, the lower two longer and wider with linear-subulate apex and with divergent lateral veins at base. Inflorescence usually eglandular, rarely sparsely glandular === P. arenaria
4 Corolla tube hairy in lower half (native) === P. coronopus and P. maritima
Corolla tube entirely glabrous === 5
5 Capsule with two seeds. Leaves linear to lanceolate === 6
Capsule with 4-numerous seeds. Leaves ovate to ovate-elliptical (native) === P. major and P. media
6 Bracts and sepals densely villous. Usually annual === P. lagopus
Bracts and sepals glabrous to shortly hairy, never villous. Usually perennial === 7
7 Anterior sepals connate for most of their length. Leaves lanceolate, 5-35 mm wide. Scapes strongly sulcate, ca. twice as long as leaves (native) === P. lanceolata
Anterior sepals almost free. Leaves linear, 1-8 mm wide. Scape terete, ca. as long as leaves === P. ovata
Additional aliens: Plantago heterophylla Nutt. (Am., wool alien), P. loeflingii L. (Medit., Atl. Isl., vector unknown) and P. myosuros Lam. (S-Am., wool alien).
Literature:
Albach D.C., Meudt H.M. & Oxelman B. (2004) Piecing together the “new” Plantaginaceae. American Journal of Botany 92(2): 297-315. [available online at: http://www.amjbot.org/content/92/2/297.full.pdf+html]
Andrzejewska-Golec E. (1999) Iridoid glucosides in Littorella uniflora (L.) Asherson. Acta Societatia Botanicorum Poloniae 68: 267-268.
Bassett I.H. (1966) Taxonomy of North American Plantago L., Section Micropsyllium Decne. Revue canadienne de botanique 44(4): 467-479.
Bassett I.H. (1967) Taxonomy of Plantago L. in North America, Sections Holopsyllium Pilger, Palaeopsyllium Pilger, and Lamprosantha Decne. Revue canadienne de botanique 45(5): 565-577.
Bassett I.H. (1973) The plantains of Canada. Monograph n° 7: 46 p.
Chalabi-Ka'bi Z. (1961) The genus Plantago in Iraq. Bull. Iraq Nat. Hist. Mus. 1(2): 1-41.
Craven L.A. (1976) A review of the genus Plantago L. in New Guinea. Contr. Herb. Austral. 13: 1-7.
Daoud H.S. (1975) The genus Plantago in Kuwait. J. Univ. Kuwait (Sci.) 2: 35-57.
Hoggard R.K., Kores P.J., Molvray M., Hoggard G.D. & Broughton D.A. (2003) Molecular systematics and biogeography of the amphibious genus Littorella (Plantaginaceae). American Journal of Botany 90: 429-435. [available online at: http://www.amjbot.org/content/90/3/429.full.pdf+html]
Kamel W.M. (2003) Plantaginaceae in the flora of Egypt: 2. Taxonomic significance of seed characters. Taeckholmia 23: 97-110.
Kimstra-Sinnema J.G. (1965) Overzicht der in Nederland gevonden inheemse en adventieve Plantago-soorten. Gorteria 2: 129-135. [available online at: http://natuurtijdschriften.nl/search?identifier=535895]
Lambinon J. (1995) Notes taxonomiques, nomenclaturales et chorologiques relatives à la quatrième édition de la « Nouvelle Flore » de la Belgique et des régions voisines. 3. Données nouvelles sur des plantes adventices ou subspontanées en Belgique. Dumortiera 60: 1-36. [available online at: http://alienplantsbelgium.be/sites/alienplantsbelgium.be/files/dum60%20COMPLETE.pdf]
Lambinon J. & Verloove F. (avec coll. Delvosalle L., Toussaint B., Geerinck D., Hoste I., Van Rossum F., Cornier B., Schumacker R., Vanderpoorten A. & Vannerom H.) (2012) Nouvelle Flore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des Régions voisines (Ptéridophytes et Spermatophytes). Sixième édition. Jardin botanique national de Belgique, Meise: CXXXIX + 1195 p.
Meudt H.M. (2012) A taxonomic revision of native New Zealand Plantago (Plantaginaceae). New Zealand Journal of Botany 50(2): 101-178. [available online at: http://www.tandfonline.com/doi/pdf/10.1080/0028825X.2012.671179]
Pilger R. (1937) Plantaginaceae. In: Engler A, ed. Das Pflanzenreich, IV 269 (102, heft). Leipzig: Wilhelm Engelmann. [available online at: http://biodiversitylibrary.org/item/71651#page/7/mode/1up]
Rahn K. (1974) Plantago section Virginica: a taxonomic revision of a group of American plantains using experimental, taximetric and classical methods. Dansk. Bot. Ark. 30(2): 1-180.
Rahn K. (1978) Nomenclatorial changes within the genus Plantago L., Infraspecific taxa and subdivisions of the genus. Botanisk Tidsskrift 73: 106-111.
Rahn K. (1979) Plantago ser. Ovatae: a taxonomic revision. Bot. Tidsskr. 74(1): 13-20.
Rahn K. (1979) Plantago ser. Gnaphaloides Rahn: a taxonomic revision. Bot. Tidsskr. 73(3-4): 137-154.
Rahn K. (1981) Plantago ser. Sericeae, a taxonomic revision. Nordic J. Bot. 1(3): 297-323.
Rahn K. (1982) Plantago ser. Hispidulae, a taxonomic revision. Nordic J. Bot. 2(1): 29-39.
Rahn K. (1983) Phenetic and phylogenetic studies based on measurements of Plantago ser. Brasilienses. Nordic J. Bot. 3(3): 319-329.
Rahn K. (1983) Plantago ser. Brasilienses, a taxonomic revision. Nordic J. Bot. 3(3): 331-342.
Rahn K. (1984) Plantago sect. Oliganthos in southern South America, a taxonomic revision. Nordic J. Bot. 4(5): 601-627.
Rahn K. (1985) Plantago sect. Carpophorae, a taxonomic study. Nordic J. Bot. 5(2): 143-151.
Rahn K. (1992) Trichomes within the Plantaginaceae. Nord. J. Bot. 12: 3-12.
Rahn K. (1996) A phylogenetic study of the Plantaginaceae. Botanical Journal of the Linnean Society 120: 145-198.
Rønsted N., Chase M.W., Albach D.C. & Bello M.A. (2002) Phylogenetic relationships within Plantago (Plantaginaceae): evidence from nuclear ribosomal ITS and plastid trnL-F sequence data. Botanical Journal of the Linnean Society 139: 323-338. [available online at: http://www.rjb.csic.es/jardinbotanico/ficheros/documentos/pdf/pubinv/abg/BJLS_2002_139_323-338.pdf]
Shehata A.A. & Loufty M.H.A. (2006) On the taxonomy of Plantaginaceae Juss. sensu lato: evidence from SEM of the seed coat. Turk. J. Bot. 30: 71-84. [available online at: http://journals.tubitak.gov.tr/botany/issues/bot-06-30-2/bot-30-2-2-0502-6.pdf]
Shipunov A.B. (2000) Species generum Plantago L. et Psyllium Mill (Plantaginaceae) in flora Europae orientalis (in Russian). Novosti Sist. Vyssh. Rast. 32: 139-152.
Shipunov A. (2018) Plantagineae of the World. Available online at: http://ashipunov.info/shipunov/plantago/plantagineae_key.pdf.
Sivinski R. (2001) The genus Plantago (Plantaginaceae) in New Mexico. The New Mexico Botanist 18: 1-3. [available online at: http://www.npsnm.org/pubpdfs/18.pdf]
Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.
Tay M.L. (2008) Evolution of Australasian Plantago (Plantaginaceae). A thesis submitted in part fulfillment of the requirements for the degree of Master of Science in Ecology and Biodiversity at Victoria University of Wellington. [available online at: http://researcharchive.vuw.ac.nz/xmlui/bitstream/handle/10063/357/thesis.pdf?sequence=1]
Tison J.-M. & de Foucault B. (coord.) 2014) Flora Gallica. Flore de France. Editions Biotope, Mèze : xx + 1196 p.
Verloove F., Hoste I. & Lambinon J. (2014) Casuals omitted from the sixth edition of Nouvelle Flore de la Belgique. Dumortiera 104: 74-82. [available online at: http://www.br.fgov.be/DUMORTIERA/DUM_104/Dum_104_74-82_NF-6_Omitted_casuals.pdf]