Stemodia lanceolata Bentham (1846: 384)

Scatigna, André Vito, Sosa, Maria De Las Mercedes, Souza, Vinicius Castro & Simões, André Olmos, 2018, The identity of Stemodia lanceolata (Plantaginaceae) and its occurrence in Brazil, Phytotaxa 375 (1), pp. 121-129 : 122-127

Stemodia lanceolata Bentham (1846: 384) . Stemodiacra lanceolata (Benth.) Kuntze (1891: 466) . Lectotype (designated by Turner & Cowan 1993b):— ARGENTINA. “In Andibus Mendozae”, Gillies s.n. (K barcode K000529091 !;

isolectotype OXF not seen). Residual syntype:— ARGENTINA. “In Banda orientali et prov. La Plata”, Tweedie s.n.

(K barcode K000529092!). ( Figs. 1 & 2 ).

Stemodia lanceolata f. angustifolia Chodat & Hassler (1904: 287) . S. lanceolata var. angustifolia (Chodat & Hassl.) Minod (1918: 210) . Lectotype (first-step designated by Turner & Cowan 1993b, second-step designated here):— PARAGUAY, “ad ripam lacus Ypacaray”, 1898–1899, Hassler 3035 (G barcode G00306654 !, isolectotypes: BM barcode BM000953299 !, G barcodes G00306680 ! & G00306679 !, GH barcode 00091756 [digital image]!, K barcode K000528925 [digital image]!, UC barcode UC 944821 [digital image]!).

Stemodia lanceolata f. latifolia Chodat & Hassler (1904: 287) . Stemodia lanceolata var. latifolia (Chodat & Hassl.) Minod (1918: 211) . Lectotype (first-step designated by Turner & Cowan 1993b, second-step designated here). Paraguay. “in stagnis pr. Concepción ”, IX 1901 –1902, E. Hassler 7473 (G barcode G00306648 !; isolectotypes: BM barcode BM000953300 !, G barcodes G00306649 !, G00306652 [two sheets]! & G00306650 [two sheets]!, GH barcode 00091757 [digital image]!, K barcode K000528929 [digital image]!, MICH barcode 1108070 [digital image]!, MO stamp no. 1573387 [digital image]! MPU barcode MPU020206 [digital image]!, NY barcodes 00130682 [digital image]! & 00130681 [digital image]!, PH barcode 00022857 [digital image]!, S Herb. No. S 10-20768 [digital image]!, UC barcode UC 935131 [digital image]!).

Stemodia lanceolata f. laxiflora Chodat & Hassler (1904: 287) . Lectotype (first-step designated by Turner & Cowan 1993b, second-step designated here). Paraguay: “in palude pr. Tobaty ”, IX 1900, Hassler 6385 (G barcode G00306645 ; isolectotypes: BM barcode BM000098448 !, G barcode G00306647 !, S Herb.No. S 10-20769 [digital image]!, UC barcode UC 944820 [digital image]!). Specimen excluded: G barcode G00306646 !.

Herbs, rhizomatous, stiffly erect, sticky and aromatic, 0.3–1.5 m tall. Stems sub-quadrangular, single or sparsely branched at base, glandular-pubescent, denser towards apex. Leaves opposite to 3–4-whorled, sessile; blades lanceolate, narrow-elliptic, or oblanceolate, 2.5–9 cm × 0.5–2 cm, apex acute to acuminate, base truncate to slightly auriculate, clasping, margins sub-entire, dentate, serrate to argute-serrate, especially on distal half, abaxial surface sparsely glandular-pubescent, with short capitate trichomes concentrated on veins, adaxial surface glandular-pubescent, with short capitate trichomes scattered over surface. Flowers axillary, single or geminate, bi-bracteolate, sessile to short-pedicelate, concentrated on apex of branches, forming well defined spiciform inflorescence; bracts leaf-like, lanceolate to linear-triangular, 1–9 cm × 0.5–1 cm, usually as long as to over to times as long as flowers, apex acute to long-acuminate, frequently curved outwards, giving a filamentous aspect to the inflorescence, base acute to slightly auriculate, clasping, margins entire or dentate, serrate to argute-serrate, indument same as leaves; pedicel up to 2 mm long, sometimes twice longer in fruits, glandular-pubescent; bracteoles 2, opposite, appressed to calyx, linear 7–9 × 0.5– 0.6 mm, frequently longer than sepals, glandular-pubescent on both faces; sepals equal to sub-equal, linear-triangular 4–7 × 0.8–1 mm, abaxial surface glandular-pubescent, adaxial glabrous; corolla bilabiate, white to lilac, yellowish on throat, with purplish veins, tube 7–10 mm long, externally glandular pubescent on veins, internally sparsely glandular-pubescent, upper lip obscurely 2-lobed, ca. 5–5.1 × 4.5–4.6 mm, apex truncate to slightly emarginated, externally glandular-pubescent, internally glabrous, lower lip clearly 3-lobed, lobes 3.9–4.2 × 2–2.1 mm, externally glandular-pubescent, internally sparsely villous on central lobe up to filaments insertion, glabrous in lateral lobes, apices truncate to mucronulate. Stamens 4, didynamous, reaching throat, filaments filiform, inserted at half of corolla tube, apex capitate, anterior pair 4–4.5 mm long, posterior 1.8–2.1 mm long, glabrous; anthers with 2 fertile thecae, separated by the connective, 0.5–1.1 mm long, glabrous; staminode 1, much reduced. Ovary superior, syncarpous, 2-carpelar, 2-locular, ovoid, ca. 2–3 × 1–1.5 mm, with two opposite longitudinal grooves, glabrous; placentation axillary, ovules numerous; style terminal, filiform, 5–5.5 mm long, glabrous, persistent; stigma slightly bi-globular, 0.5–0.6 mm long, down-curved, glabrous. Capsule ovoid, 4–5.2 × 3–3.5 mm, dehiscence both loculicidal and septicidal on apical portion, glabrous. Seeds cylindrical, 0.28–0.5 × 0.1–0.2 mm, base acuminate, reticulate, longitudinally ribbed.

Specimens examined: — BRAZIL. Mato Grosso do Sul: Corumbá, invernada Barreiro, a 50 m da invernada Braque , Fazenda Acurizal , Nabileque , Pantanal , 19º44’S, 57º06’W, 24 June 1987, fl., Pott et al. 3033 ( CPAP!, UEC!) ; Fazenda Acurizal, Nabileque, Pantanal , 19º52’S, 57º08’W, 7 December 1987, Pott et al. 4079 ( CPAP!) Miranda, Rodovia BR 262 , Passo do Lontra , 16 April 1972, fl., fr., Hatschbach 29564 ( CTES!, MBM!, NY [digital image]!) ; Porto Murtinho, Ingazeira, Fazenda Ovo de Ema , depressão úmida, 16 November 2006, fl., fr., Barbosa & Silva 1922 ( ESA!, MBM!) ; Estrada para o Norte, Fazenda Tarumã , orla do brejo, 20 October 2003, fl., fr., Hatschbach et al. 76566 ( ESA!, MBM!) ; Fazenda Panorama , área alagada na margem do corredor próximo à sede, 21º36’27”S, 57º38’17”W, 5 June 2017, fl., Scatigna et al. 1210 ( UEC!) ; Fazenda Retiro Conceição , área alagada ao lado de corredor, 21º42’15”S, 57º45’48”W, 5 June 2017, fl., fr., Scatigna et al. 1212 ( UEC!) ; Rio Grande do Sul: São Gabriel, Fazenda Sta. Cecilia , “in dumetosis subpaludosis”, January 1944, fl., fr., Rambo s.n. ( PACA 25832 !) .

Distribution and habitat: — Stemodia lanceolata is restricted to South America, being previously recorded in Argentina, Bolivia and Paraguay (Sosa & Dematteis 2013). In Brazil, this species was collected in the states of Rio Grande do Sul and Mato Grosso do Sul ( Fig. 3 ). Specimens grow in moist soil, in open, often disturbed, areas of flooded grasslands and Chaco ( Fig. 2C ).

Phenology: — Stemodia lanceolata was collected with flowers and fruits in January, February, April, June, September, October and November. It is likely to produce flowers and fruits whenever there is water available. Plants exhibit vegetative propagation by aerial rhizomes.

Typifications: — Turner & Cowan (1993b) effectively lectotypified the names treated here, and apparently annotated the specimens properly; nevertheless, we believe that it might be narrowed according to Art. 9.17 of the ICN ( Turland et al. 2018), in order to simplify and avoid confusion in further citation of the original materials. For Stemodia lanceolata f. angustifolia , the authors selected the specimen Hassler 3035 housed at G as the lectotype and a duplicate at G-DEL as an isolectotype; however, the collection of G-DEL has been incorporated in the general collection of G, in which we found three duplicates of the same gathering. We selected the specimen annotated as lectotype by B. Turner, bearing the label of Hassler’s herbarium, as second-step lectotype (barcode G00306654), while the remaining specimens, both annotated as isolectotype by Turner, are here considered isolectotypes. For S. lanceolata f. latifolia , the authors selected a specimen at G-DEL of Hassler 7473 as the lectotype and a duplicate at G as one of the isolectotypes, but we found, in the general collection, four duplicates of the same gathering, two of them mounted in two sheets each. We selected the specimen bearing the label from Delessert’s herbarium and annotated as lectotype by B. Turner as the second-step lectotype (barcode G00306648), and considered the remaining specimens, all of them annotated as isolectotype by Turner, as isolectotypes. Finally, for S. lanceolata f. laxiflora, Turner & Cowan (1993b) selected a specimen of Hassler 6385 at G as the lectotype and a duplicate at G-BOIS (also incorporated in G) as isolectotype, but we found three duplicates of this gathering in the general collection; we selected the specimen bearing a label from Chodat’s herbarium and annotated as lectotype by Turner as the second-step lectotype (barcode G00306645), and considered the specimen bearing a label from Hassler’s herbarium and annotated as isolectotype by Turner as an isolectotype (barcode G00306647). The third duplicate of Hassler 6385 (barcode G00306646) bears a label from Boissier’s herbarium and the location of “Cerros de Tobaty”, presumably a different location from that cited in the protologue; therefore, we considered it as belonging to a different gathering, although it has been annotated as isolectotype by Turner.

Discussion: — Stemodia lanceolata presents erect habit ( Fig. 2B ), sessile leaves with clasping base ( Fig. 1B ), and sessile or short-pedicelate flowers ( Fig. 1C ), each one subtended by a pair of bracteoles right below the calyx ( Fig. 1D ), concentrated at the apex of branches ( Figs. 1A, 1C , 2A ), a set of traits that, according to Souza & Giulietti (2009) and Scatigna et al. (2018) approximate it to S. durantifolia , S. hyptoides Chamisso & Schlechtendal (1828: 8) , S. maritima Linnaeus (1759: 1118) , S. palustris Saint-Hilaire (1824–1826: 216), S. perfoliata Scatigna & V.C.Souza in Scatigna et al. (2018: 253) and S. stricta . Some of these taxa are of difficult identification, which has led to conflicting circumscriptions (Dawson 1979, Turner & Cowan 1993b, Souza & Giulietti 2009, Sosa & Dematteis 2013). In addition, records of intermediate specimens suggest that hybridization may occur among some species, contributing to the taxonomic confusion in the called Stemodia stricta complex (Sosa et al. 2012). In Brazilian herbaria, the few specimens belonging to S. lanceolata have been identified either as S. stricta or S. durantifolia , especially due to the presence of short, capitate trichomes on sepals, a feature used by Souza & Giulietti (2009) to differentiate these species from S. hyptoides ; however, there are some morphotypes of S. hyptoides that exhibit this type of trichomes on sepals, proving the fragility of this character as diagnostic (Sosa et al. 2012). The size of flowers has long been used to characterize S. lanceolata (Minod 1918, Turner & Cowan 1993a, 1993b), but this feature currently presents intra- and interspecific variation and overlap (Sosa et al. 2012, Sosa & Dematteis 2013).

Stemodia lanceolata is characterized by the long, lanceolate leaves that frequently turn blackish after herborization, and by the long linear-triangular bracts, with a linear, out-curved apex that give a filamentous aspect to the terminal inflorescences ( Figs. 1C , 2A ). This species differs from S. stricta in the more robust and taller habit, in the larger leaves distributed throughout the stem (vs. concentrated at base), in the erect inflorescence (vs. frequently flexuous), in the bracts longer than flowers (vs. shorter), and in the sepals longer than half of the corolla tube (vs. shorter). It differs from S. durantifolia in the taller habit, in the bracts as long as to over two times as long as the flowers (vs. usually as long as or slightly longer than the flowers) with the apices linear and curved outwards (vs. acute, patent or incurved). Stemodia lanceolata differs from S. hyptoides in the terminal inflorescence (vs. axillary), in the bracts longer than flower (vs. shorter), and in the sepals longer than half of the corolla tube (vs. shorter). A comparison between S. lanceolata , S. stricta and S. scoparioides was provided by Sosa & Dematteis (2012) using some characters, such as corolla length and leaf shape, that may overlap with our updated description. We summarized additional characters that are helpful in diagnosis in Table 1.

Stemodia ericifolia (Kuntze 1898: 239) Schumann (1900: 395) and S. hassleriana Chodat in Chodat & Hassler (1904: 287), both species previously known to occur in Argentina and/or Paraguay, near Brazilian borders, were also kept out from the account by Souza & Giulietti (2009), but their occurrence in Brazil is clearly documented (Pott & Pott 2000, Sosa 2010, BFG 2015). At this point, Brazil counts with 19 species of Stemodia , but it is possible that other species from neighbor countries, such as S. diplohyptoides Sosa & Dematteis (2014: 272) , from Argentina, and S. scoparioides , from Paraguay, may be found in Brazilian territory if further collection efforts are concentrated at border regions.

Figures

FIGURE 1. Stemodia lanceolata. A. Flowering branch. B. Leaf base clasping the stem; C. Inflorescence apex; D. Flower; E. Immature fruit with persistent calyx subtended by two bracteoles. F. Detail of sepal surface showing glandular trichomes. G. Dissected corolla showing androecium. H–I. Stamens. [Drawn by Mirtha L. Gómez after Hatschbach 29564(CTES)].

FIGURE 2. Stemodia lanceolata. A. Inflorescence with linear, out-curved bract apices and white flowers. B. Habit in flooded habitat; C. Habit: flooded chaco. Photos:A.V. Scatigna.

FIGURE 3. Distribution map of Stemodia lanceolata in Brazil. Black circles are cited records.