Tillandsia uruguayensis Rossado

Rossado, Andrés J., Donadío, Sabina & Bonifacino, José M., 2024, A taxonomic revision of Tillandsia (Tillandsioideae, Bromeliaceae) from Uruguay, Phytotaxa 667 (1), pp. 1-90 : 1-90

15. Tillandsia uruguayensis Rossado in Rossado et al. (2018a: 134). Figs. 9B , 40 , and 41.

Type (holotype):— URUGUAY. Rivera: “Cerro Batoví Dorado, paredones de arenisca endurecida”, 30 August 2001, Brussa s.n. ( MVFA 29683 !) .

Plants caulescent, much branched from the base and forming dense clumps up to 60 cm in diameter but generally smaller. Roots up to 2.5 mm in diameter, present all along the stem. Stems up to 1 m long but frequently much shorter, when long pendant for most of its length and apically ascending. Leaves spirally arranged, clustered in the apex of the stem, gray; sheaths 15–31 mm wide, gradually merging into blades, densely lepidote except for the glabrous very base; blades 55–165 × 5–18 mm, erect to divergent (sometimes the older one spreading), sometimes turning secund, very narrowly triangular, markedly channelled all along, fleshy, densely tomentose-lepidote throughout, trichomes asymmetric. Inflorescences simple; peduncles wholly covered by bracts, (4.4–)5.5–22(–27.5) cm long, 1.8–3 mm in diameter, glabrous; peduncle bracts 6 to 9(13) in number (the basal ones leaf-like), erect, evenly distributed along the peduncle, densely imbricate (at least 2 times longer than the internodes); upper peduncle bract bladeless, (26–)31–50(–56) × 8–14 mm, narrowly elliptic-triangular to narrowly elliptic, grayish-green or grayish-red, sparsely to densely lepidote except for the usually glabrous base. Spike distichously and densely (2)4 to 13(16)-flowered, 40–110(–150) mm long, strongly complanate, narrowly elliptic in outline; rachis totally hidden by the floral bracts or sometimes partially exposed, green, glabrous. Floral bracts densely imbricate, 2–5 times longer than the internodes, clasping the basal half of the flower, bladeless, narrowly elliptic to narrowly triangular, ecarinate, light green, yellowish-green, reddish or light pink; basal floral bracts 25–45(–51) × 8–14 mm, exceeding the sepals by 8–23 mm, densely lepidote to glabrescent or less frequently glabrous, trichomes generally denser or concentrated towards the apex only; upper floral bracts shorter, usually glabrous. Flowers 36–57 mm long, scentless; sepals hidden by floral bracts, 15–27 × 3.5–7.3 mm, evenly very short connate at the base for less than 1 mm (appearing free), narrowly elliptic to narrowly elliptic-ovate, light pink to greenish, glabrous; abaxial sepal ecarinate; adaxial sepals strongly carinate, and generally longer and wider than the abaxial one; petals 36–57 mm long, spatulate; claw 3–4 mm wide; limb 5.7–10.5 mm wide, divergent to spreading, elliptic, white, margins softly crenate; stamens 30–45 mm long, included (reaching the throat of the corolla), shorter than the pistil; filaments 24–37 mm long, straight (not plicate); pollen yellow; pistil 32–52 mm long, slightly exserted; ovary 3.5–7 × 1.5–3.6 mm, ovoid, tapering into the style; style 25–45 mm long, ca. 6–8 times as long as the ovary, white; stigmas simple-patent. Capsules 19–30 × 4–6 mm, not exceeding or barely exceeding its respective floral bract, narrowly ellipsoid-prismatic, apex acute and beaked.

Vernacular names:— Clavel del aire blanco ( Brito & Llano 2008).

Classification:— Tillandsia uruguayensis belongs to T. subg. Aerobia ( Rossado et al. 2018a) .

Distribution and habitat:— Tillandsia uruguayensis is an endemic species to northern Uruguay (Artigas, Rivera, and Tacuarembó departments; Fig. 41 ), where it grows epilithically on pillars or rock walls associated to the “Cuchilla de Haedo” hill system ( Fig. 40A–C ). This xeromorphic species establishes almost exclusive communities, although it occasionally coexists with Dyckia ( Bromeliaceae ) and cacti. Occasionally, T. uruguayensis grows as an epiphyte on trees close to the rocky surfaces where it is more abundant.

It is noteworthy that, since its original publication in 2018, new populations of this species have been documented in Uruguay, and it is likely that more populations will be discovered in southern Brazil.

Phenology:— Tillandsia uruguayensis flowers from late winter to mid-spring, with peak blooming in September and October ( Fig. 4 ). Fruiting occurs as of October and seed dispersal from late February to April (late summer–early autumn). The development of the inflorescence (from emergence to first open flower) takes between three and six months, and the complete reproductive cycle lasts from eight to eleven months.

Reproductive observations:— The inflorescences of T. uruguayensis remain in flower for about 15 to 40 days depending on their size. The number of open flowers per inflorescence at any given time is generally two, although this may vary from one to three. Individual flowers are open from four to seven days (occasionally three or up to eight) and once they wither, their petals change from white to semi-transparent (similar to T. arequitae and T. xiphioides ). Following the flowering period, both the peduncle and floral bracts turn stramineous and dry up. We have observed hummingbirds visiting the flowers of T. uruguayensis in its natural habitats.

Conservation assessment:— The estimated EOO and AOO for Tillandsia uruguayensis were 5,046 km 2 and 64 km 2, respectively. The distribution of this species in Uruguay is discontinuous, with several groups of populations often situated at considerable distances from each other (fragmented distribution). Most of these populations inhabit well-preserved habitats, and some feature a high number of individuals. However, some of these populations are threatened by Pinus plantations, which overshadow the Tillandsia plants, causing them to gradually die over time due to lack of proper light.

Considering these factors alongside the EOO results, we tentatively propose classifying T. uruguayensis as Vulnerable (VU) (B1-a and biii criteria of the IUCN guidelines). Tillandsia uruguayensis occurs in the national protected area: ‘Paisaje protegido Valle del Lunarejo’.

Diagnostic characters:— The characters distinguishing Tillandsia uruguayensis from its congeneric relatives in Uruguay are spirally arranged leaves with their blades strongly channelled from the base, distichously arranged flowers, and floral bracts 25–51 mm long.

In Uruguay, Tillandsia arequitae is morphologically the closest species to T. uruguayensis . Both species form dense and gray clumps that grow in full sun on vertical rock walls. However, their populations are geographically distant, inhabiting distinct hill systems (known as “Cuchillas”); T. uruguayensis is distributed in northern Uruguay, growing on pillars or rock walls associated with the Cuchilla de Haedo ( Fig. 41 ), while T. arequitae occurs exclusively in southeastern Uruguay, growing on hills of the Cuchilla Grande ( Fig. 11 ).

Background in Uruguay:— Tillandsia uruguayensis was published in 2018 based on herbarium specimens collected in Uruguay. The oldest gathering of T. uruguayensis for the country dates back to 1900 (Arechavaleta s.n., MVM 2947).

Representative specimens examined:— URUGUAY. Artigas: Arroyo Maneco , 19 Mayo 2012 (cultivated in Canelones, pressed 12 Ocotber 2014), Berazategui s.n. ( MVJB 33109 ) . Rivera: Cerro Batoví Dorado , 10 October 2015, Rossado & Bonifacino 418 ( MVFA, SI, WU) . Tacuarembó: Gruta de los Cuervos , 21 October 2005, Brussa s.n. ( MVJB 23750 ) .

Figures

FIGURE 4. Phenology of Tillandsia species occurring in Uruguay. Divisions within each month indicate intervals of approximately 10 days, identified as the beginning, middle, and end of each month. Tillandsia loliacea is excluded due to lack of enough information. * Denotes species with cleistogamous flowers. ** Denotes species with insufficient data to ascertain the timing of fruiting or fruit dehiscence.

FIGURE 9. Illustrations of floral parts. A. Tillandsia arequitae. B. T. uruguayensis. C. T. xiphioides. From left to right: floral bract (stretched view), sepal (stretched view), petal (stretched view), and pistil. A based on Rossado 402 (MVFA); B based on Rossado & Bonifacino 418 (MVFA); C based on Rossado 377 (MVJB).

FIGURE 11. Distribution map of Tillandsia arequitae.

FIGURE 40. Tillandsia uruguayensis.A. Habitat; rocky cliffs of de la Jabonería stream (ca. Valle Edén, Tacuarembó, Uruguay). B. Close up of habitat; Cascada Grande (Rivera-Tacuarembó, Uruguay). C. Habit (Pilares de Klinger, Tacuarembó, Uruguay). D. Inflorescences (Batoví Dorado Hill, Rivera, Uruguay).E. Close upof the Inflorescences.Noticecolor variation ofbracts.F. Fertilepart of the inflorescence. G. Lateral view of the flower (floral bract removed). H. Front view of the flower. I. Capsule. Photos by Andrés Rossado.

FIGURE 41. Distribution map of Tillandsia uruguayensis.