Plantago napiformis (Rahn) Hassemer

Hassemer, Gustavo, 2017, Contributions to the knowledge of the genus Plantago (Plantaginaceae) in the Central-West region of Brazil, Phytotaxa 316 (1), pp. 1-21 : 15-18

Plantago napiformis (Rahn) Hassemer in Hassemer et al. (2015b: 229–231)

≡ P. paralias subsp. napiformis Rahn (1964: 56–57)

≡ P. tomentosa subsp. napiformis (Rahn) Rahn (1974: 139–141)

Type: — ARGENTINA. CORRIENTES: Empedrado: Estancia Las Tres Marías, dry grassland on the top of the bank of Río Paraná , soil black earth, 22 November 1962, T. M. Pedersen 6650 (holotype C-10016664!; isotype P-04046403!) .

Description: —Rosette herbs, perennial. Taproot thickened, usually swollen above, distinctly napiform ( Fig. 10 ). Caudex generally inconspicuous, to 2 cm long, normally without a conspicuous tuft of reddish trichomes at its apex. Leaves oblanceolate or obovate, basally attenuated, without a very evident petiole, membranaceous to papiraceous, pilose. Trichomes on leaves and scapes ribbon-shaped, compressed, with very conspicuous cellular articulations, perceptibly gradually tapering towards the apex (type G); those on scapes patent. Spike multiflowered, with flowers densely packed above, less densely crowded below. Corolla actinomorphic, glabrous, remaining very conspicuous after fruit maturation. Stamens 4. Pyxidia 3(–4)-seeded. Seeds slightly convex to slightly concave ventrally, convex dorsally; surface reticulate. See also the description in Hassemer et al. (2015b: 230).

Illustrations: — Fig. 7 in Rahn (1964); Fig. 78 in Rahn (1974); Fig. 1 in Hassemer et al. (2015b).

Photographs: — Figs. 10 and 11 .

Distribution: —This species was hitherto recorded in Paraguay, northeastern Argentina (Chaco, Corrientes, Formosa, Misiones and Santa Fe provinces) and southern Brazil (western Rio Grande do Sul, in the municipalities of Giruá and Santa Maria) (see Fig. 3 in Hassemer et al. 2015b). Here I present the first records of P. napiformis in the Central-West region of Brazil, where it has been collected in Mato Grosso do Sul, in the municipalities of Amambai and Ponta Porã ( Fig. 7 ).

Habitat: —Open areas, mainly native grasslands and ruderal environments ( Fig. 11 ).

Conservation status: —Least concern (LC). This species was previously assessed as near threatened (NT) ( Hassemer et al. 2015b), but with more field work and herbarium revisions I discovered that P. napiformis is more frequent and has a wider range than previously thought, including ruderal environments ( Fig. 11 ). I thus consider it safe to re-assess its conservation status as least concern.

Notes: —The new records were discovered during field work in Mato Grosso do Sul in October 2015, and herbarium revisions. Some specimens of P. napiformis , all from Mato Grosso do Sul, were identified as P. tomentosa Lamarck (1791: 340) prior to my herbarium revisions. This can be explained by the fact that until recently P. napiformis was recognised as a subspecies of P. tomentosa ( Rahn 1974, Hassemer et al. 2015b). However, I must highlight that very important morphological differences distinguish these two species, the most important being the surface of the seeds (reticulate in P. napiformis , rugose in P. tomentosa ), and the trichomes (wide, stiff, ribbon-shaped and compressed in P. napiformis ; slender, filiform and terete in P. tomentosa ) ( Hassemer et al. 2015b). With my herbarium revisions I concluded that P. tomentosa does not occur in the Central-West region of Brazil, and most of the specimens previously identified as P. tomentosa from this region were shown to belong to P. napiformis instead. Furthermore, with the new records the known distribution of P. napiformis was extended ca. 150 km northwards.

Additional specimens examined: — BRAZIL. MATO GROSSO DO SUL: Amambai: Escola Agrotécnica de Primeiro Grau Lino do Amaral Cardinal , 3 October 1993, P. C. Palhano 18 (CGMS-8175, FLOR) ; Fazenda-escola da prefeitura municipal, 24 July 1995, E. Scremin-Dias et al. 250 (CGMS-4951, FLOR) ; Ponta Porã: estacionamento em frente à loja da Calçados Nacional, Rua Dom Pedro II, esquina com a Avenida Marechal Floriano, 22°32’39” S, 055°43’31” W, 669 m, 14 October 2015, G. Hassemer & J. M. da Silva 809 ( B, C, CGMS, DDMS, FT, FURB, K, MBM, MVFA, P, UFMT, W, WELT) ; gramado no meio-fio, no cruzamento da Avenida Brasil com a Rua Baltazar Saldanha, 22°31’52” S, 055°43’59” W, 659 m, 15 October 2015, G. Hassemer & J. M. da Silva 810 ( C) .

Figures

FIGURE 1. Lectotype of Plantago hirtella (A.J.A. Bonpland & F.W.H.A. von Humboldt s.n., P-00670059). Published with permission of Muséum National d’Histoire Naturelle.Available online at: https://science.mnhn.fr/institution/mnhn/collection/p/item/p00670059.

FIGURE 3. Lectotype of Plantago leptophylla (A. Isabelle s.n., P-03530099). Published with permission of Muséum National d’Histoire Naturelle.Available online at: https://science.mnhn.fr/institution/mnhn/collection/p/item/p03530099.

FIGURE 7. Distribution of Plantago commersoniana (purple squares, the new record in orange), P. hatschbachiana (red triangles) and P. napiformis (green dots, the new records in yellow); the new records of P. australis subsp. hirtella in the Central-West region of Brazil (blue diamonds); and the new records of P.major in Mato Grosso state (pink stars). The area in the map shaded in blue corresponds to the states in Brazil where the occurrence of P. australis subsp. hirtella had been hitherto recorded.

FIGURE 10. Detail of an uprooted specimen of Plantago napiformis showing the distinctive, taxonomically important napiform taproot.

FIGURE 11. Examples of ruderal environments where populations of Plantago napiformis were found in Ponta Porã, Mato Grosso do Sul. A: Amidst rocks in a car park. B: Lawns on the roadside.