Viridantha secundifolia (Ehlers) Hern.-Cárdenas, Espejo & López-Ferr., comb. et stat. nov. Phytokeys 132: 99-110. 2019
Basionym. Tillandsia mauryana L.B. Sm. forma secundifolia Ehlers, Die Bromelie. Sonderheft 6: 56–60. Figs pp. 56, 57, 60. 2009.
Type. MEXICO. Hidalgo: Metztitlán, 1300 m a.s.l., 12 February 1992, J. Lautner L92/3 (holotype: MEXU not found); Hidalgo, prope Tolantongo “Tolontogo”, 1900 m a.s.l., 22 February 2006, R. Ehlers & M. Kretz EM061802 (paratype: WU not found). Lectotype (here designated): figure page 56, Die Bromelie. Sonderheft 6: 56-60. 2009.
Plants saxicolous, flowering 10–13 cm tall, 12–14 cm diameter; rosettes acaulescent, solitary or caespitose, falcate in outline.
Leaves numerous, longer than the inflorescence;
sheaths pale brown on both surfaces, broadly oblong to nearly square, 1–1.2 cm long, 0.8–1.1 cm wide, glabrous towards the base on both surfaces;
blades falcate, densely white-greyish lepidote, narrowly triangular, 4.5–7 cm long, 0.5– 0.8 cm wide, apical portion long attenuate.
Inflorescence short pedunculated, falcate, one-branched, with 3–5 spikes;
peduncle 1–1.5 cm long, 3–5 mm diameter, covered by the peduncle bracts;
peduncle bracts similar to the leaves but reducing in size towards the apical portion, densely white-greyish lepidote;
spikes reddish-rose, erect and appressed, flattened, elliptic, 2.5–3.5 cm long, 1–1.5 cm wide;
flowers distichous, erect and appressed, 3–5 by spike;
floral bracts reddish-rose at the apex, yellowish-green towards the base, ovate, 1.8–2 cm long, 0.7–1.2 cm wide, apex acute to acuminate, ecarinate to slightly carinate at the apex, lepidote abaxially;
sepals pale green, lanceolate, 1.2–1.5 cm long, 0.3–0.4 cm wide, apex acute, the two adaxial ones carinate, lepidote abaxially;
petals dark green, narrowly oblong, 2–2.5 cm long, 0.25–0.3 cm wide, apex rounded to obtuse;
filaments white, 1.4–1.6 cm long;
anthers pale to dark green, 2.5–3 mm long;
ovary broadly ovoid, 3.5–4.5 mm long, 2.5–3.5 mm diameter;
style white, 6–10 mm long, included; style branches green.
Capsules 1.5–1.8 cm long, 5–8 mm diameter;
seeds fusiform, 3–4 mm long, coma 0.8–1.2 cm long.
Habitat and ecology. Viridantha secundifolia is only known from the state of Hidalgo in the western and eastern regions of Metztitlán and Tolantongo municipalities, respectively, where it grows on vertical walls in xerophilous scrubs at elevations between 1100 and 1900 m a.s.l.
Phenology. Blooming in January and February.
Observations. Tillandsia mauryana was described by Lyman B. Smith (1937), based on specimens from the canyon of Metztitlán, in the state of Hidalgo, Mexico. Espejo-Serna (2002) transferred the species to Viridantha. Ehlers (2009) described T. mauryana L. B. Sm. forma secundifolia, differentiating it from the typical form only by the secund disposition of its leaves. Besides, Ehlers (2009) mentioned that its populations grow separated from those of T. mauryana. The detailed analysis of the morphological characteristics of living and dried specimens of T. mauryana forma mauryana and T. mauryana forma secundifolia allowed us to detect that, in addition to the characteristic mentioned by Ehlers (2009), there are other differences in the plants of both populations such as: the shape of the rosettes (falcate vs. spherical); the length (1–1.2 cm vs. 1.5–2.5 cm) and the shape (broadly oblong to square vs. broadly elliptic) of the leaf sheaths; the length of the floral bracts (1.8–2 cm vs. 1–1.5 cm), the presence or not of a keel on the floral bracts (absent or visible only in the apex vs. present along the bract); and the colour of the anthers (pale to dark green vs. black).
Viridantha grandispica (Ehlers) Hern.-Cárdenas, Espejo & López-Ferr., V. rzedowskiana Hern.-Cárdenas, Espejo & López-Ferr. and V. teloloapanensis (Ehlers & Lautner) Hern.-Cárdenas, Espejo & López-Ferr., are other species morphologically similar to V. secundifolia (Table 1). Viridantha secundifolia differs from V. grandispica in the shape of the rosettes (falcate vs. spherical); in the shape of the leaf sheaths (broadly oblong to square vs. narrowly oblong); in the presence or not of a keel on the floral bract (absent or visible only in the apex vs. present along the bract); and in the shape of the sepals (lanceolate vs. ovate).
Viridantha secundifolia differs from V. rzedowskiana in the shape of the rosettes (falcate vs. spherical); in the size of the leaf sheaths (1–1.2 cm × 0.8–1.1 cm vs. 1.8–2 cm × 1.5–1.7 cm); in the keel of the floral bract (absent or visible only in the apex vs. present along the bract); and in the shape of the sepals (lanceolate vs. ovate).
Viridantha secundifolia differs from V. teloloapanensis in the shape of the rosettes (falcate vs. spherical); in the shape of the leaf sheaths (broadly oblong to square vs. ovate); in the number of the spikes (3–5 vs. 1); and in the shape of the sepals (lanceolate vs. ovate). So we concluded that T. mauryana forma secundifolia presents different and consistent morphological characteristics to those observed on the typical form and can be considered as a distinct species.
Specimen examined. MEXICO, Hidalgo: municipio de Metztitlán. 28 km sobre el camino que va de Metztitlán a Tolantongo (20°35'43"N, 98°54'09.9"W), 1103 m a.s.l., 3 February 2018, R. Hernández-Cárdenas y A. Sarabia 2136 (UAMIZ).