Tillandsia xiphioides Ker Gawler (1816

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

18. Tillandsia xiphioides Ker Gawler (1816 : t. 105). Figs. 9C , 46 , and 47.

≡ Phytarrhiza xiphioides (Ker Gawl.) É. Morren (1879: 370) . Type (lectotype designated by Smith & Downs 1977: 815):—[Icon] t. 105 in Ker Gawler (1816)!.

= Tillandsia xiphioides var. minor L. Hromadnik (1989: 65) . Type:— ARGENTINA. San Luis: San Fransisco mountain range, San Fransisco del Monte de Oro , August 1981, H. Hromadnik & L. Hromadnik 7315 (holotype: WU0004292 [online image!]).

Plants caulescent or acaulescent, not branched to much branched from the base and then forming dense clumps up to 40 cm in diameter but generally smaller. Roots up to 2 mm in diameter, present all along the stem. Stems usually very short but sometimes up to 25 cm long, then pendant for most of its length and apically ascending. Leaves spirally arranged, clustered forming a rosette, gray; sheaths 14–20 mm wide, gradually merging into blades, densely lepidote except for the glabrous very base; blades 85–142 × 10–20 mm, suberect to reflexed, narrowly triangular to very narrowly triangular, flat (sometimes slightly channelled at the base) and then gradually channelled towards the apex, fleshy, densely tomentose-lepidote throughout, trichomes asymmetric. Inflorescences simple; peduncles wholly covered by bracts (also sometimes hidden by apical leaves), (3.5–) 5.5–14 cm long, ca. 2.5–3 mm in diameter, glabrous; peduncle bracts 5 to 9 in number (the basal ones leaf-like), erect, evenly distributed along the peduncle, densely imbricate (more than 4 times longer than the internodes); upper peduncle bract bladeless or with a very short blade, 47–70 × 10–16 mm, narrowly elliptic-triangular, yellowish-green, vinaceous or brownish-green, glabrous or sometimes with some trichomes towards the apex. Spike distichously and densely 2 to 5-flowered, 60–103 mm long, strongly complanate, very narrowly elliptic in outline; rachis mostly hidden by the floral bracts or sometimes partially exposed, green, glabrous. Floral bracts densely imbricate, 4–6 times longer than the internodes, clasping the basal half of the flower, bladeless, narrowly elliptic-triangular to narrowly ovate-elliptic, ecarinate, stramineous, greenish, yellowish-green, reddish-green but mostly vinaceous, glabrous; basal floral bracts 55–84 × 10–17 mm, exceeding the sepals by 12–37 mm. Flowers 65–100 mm long, strongly fragrant; sepals wholly hidden by floral bracts, 32–48 × 5–12 mm, evenly very short connate at the base for less than 1 mm (appearing free), narrowly elliptic to narrowly ovate-elliptic, light green to yellowish-green, glabrous; abaxial sepal ecarinate; adaxial sepals strongly carinate, and generally longer than the abaxial one; petals 85–110 mm long, spatulate; claw 6–6.5 mm wide; limb 17–30 mm wide, reflexed, elliptic to widely elliptic, white, margins undulate and strongly crenate-serrate; stamens 55–85 mm long, included (reaching the throat of the corolla), shorter than the pistil; filaments 42–73 mm long, straight (not plicate); pollen yellow; pistil 60–100 mm long, (slightly) exserted; ovary 5–9 × ca. 2.8 mm, ovoid-ellipsoid, tapering into the style; style 53–91 mm long, ca. 10 times as long as the ovary, white; stigmas simple-patent. Capsules 24–34 × 4–5.5 mm, much shorter than its respective floral bract, narrowly ellipsoid-ovoid, prismatic, apex acute and beaked.

Vernacular names:— Clavel del aire, clavel del aire blanco, Flor del aire ( Herter 1949 –1956).

Classification:— Tillandsia xiphioides is the type species of T. subg. Aerobia ( Barfuss et al. 2016) . Currently, two varieties are recognized within Tillandsia xiphioides : T. xiphioides var. xiphioides and T. xiphioides var. lutea L. Hromadnik (1990: 14) . The typical variety is the most widely distributed and is the only present in Uruguay.

Distribution and habitat:— Bolivia, Argentina, Brazil, and Uruguay. Tillandsia xiphioides is frequent and widely distributed from west-central Bolivia to central Argentina, growing as epiphyte or epilithic in arid and semiarid habitats. In Brazil, its distribution is confined to southern states, where it exclusively grows as epilithic in very few localities.

In Uruguay, Tillandsia xiphioides is a rare species. So far, only three isolated populations have been found in Cerro Largo, Maldonado, and San José departments ( Fig. 47 ). These populations are situated at considerable distances from each other, always in association with rocky habitats surrounded by xeric hillside forests or hillside scrubs. In these habitats, T. xiphioides grows epilithically on large rocky blocks or rocky walls ( Fig. 46A–B ), exposed to full sun, commonly forming almost exclusive communities or coexisting with T. aëranthos and/or cacti. Rarely, T. xiphioides is found as epiphyte on trees close to the rocky surfaces where it is more abundant.

Phenology:— Tillandsia xiphioides flowers in spring, with peak blooming from mid-October to mid-November ( Fig. 4 ). The inflorescence emergence starts mostly from April to June and takes four to six months until the first flower opens. Fruiting as of November. Seed dispersal was observed in March.

Conservation:— We consider Tillandsia xiphioides as Threatened in Uruguay. Despite its occurrence in well-preserved habitats, T. xiphioides faces threats not only due to its scarce and highly localized distribution within the country (limited to three localities) but also because live plants are collected from its natural habitats for horticultural purposes. This anthropic pressure has the potential to significantly reduce the number of individuals in the near future, or even lead to the local extinction of some populations. Complicating this challenging scenario further, the species is absent from national protected areas. In light of these facts, T. xiphioides could be at risk of extinction in Uruguay if no measures are taken to ensure its protection. Tillandsia xiphioides is considered as a priority for conservation in Uruguay by Marchesi et al. (2013).

Diagnostic characters:— Tillandsia xiphioides exhibits the largest flowers and longest floral bracts among the Tillandsia species found in Uruguay and neighboring regions, rendering it easily distinguishable from morphologically similar species such as T. arequitae .

Background in Uruguay:— Tillandsia xiphioides was first cited for Uruguay by Herter (1930), although he did not provide a reference material. Subsequently, Smith (1933) and Herter (1949 –1956) also acknowledged the presence of this species in the country, but it was Smith (1972) the first to include reference to actual specimens. The oldest known gathering of T. xiphioides for the country dates back to 1894 (“Señorita de” Larriera s.n., MVM) for San José department.

Note I:— Here we follow the proposal of Gouda (2020), in which Tillandsia xiphioides var. minor is regarded as a synonym of T. xiphioides . In this sense, it is worth mentioning that despite the citation of T. xiphioide s var. minor for Uruguay by Brito & Llano (2008), all the specimens reported in that work under this name correspond entirely to T. uruguayensis .

Note II: — Tillandsia xiphioides was described by Ker-Gawler (1816) based on a plant from Buenos Aires (as “ Buenos Ayres ”) and cultivated in Devon (as “ Devonshire ”). In 1935, Smith explained that he searched specimens in Kew , the British Museum , and Cambridge but found none. The species is validly lectotypified by Smith & Downs (1977), who, under T. xiphioides , stated: “ TYPE. Probably none extant. Species adequately typified by original description and plate” .

It is worth mentioning that, although the original description mentions Buenos Aires as the origin of the material upon which the description was based on, it is probable that the plant was not originally collected in Buenos Aires, as there are no herbarium specimens supporting the distribution of T. xiphioides within this province. Instead, it was likely obtained from other areas in Argentina where the species is commonly found.

Representative specimens examined:— URUGUAY. Cerro Largo: Cerca de Paso Pereira , 2 November 2014, Rossado et al. 384 ( MVFA) . Maldonado: Cerro Pan de Azúcar , 16 November 2019, Rossado et al. 583 ( MVFA) . San José: Sierra de Mahoma , December 1894, “Señorita de” Larriera s.n. ( MVM – Herb. Osten 3122) .

Doubtful entities from the Uruguayan flora

Tillandsia lorentziana Grisebach (1874: 271) . Type (lectotype designated by Smith & Downs 1977: 801 [as “ holotype ”]):—[ ARGENTINA]. Córdoba: “auf trockenen Felsen bei Las Peñas im Thale des Arroyo”, February 1871, Lorentz 69 (B 10 0243511 [online image!]; isolectotypes: BR0000008846174 [online image!], CORD00004744 [online image!], GH00029432 [online image!], GOET006702 [online image!], GOET006703 [image!], NY00247353 [online image!]).

Tillandsia lorentziana has never been cited for Uruguay. However, we found an old specimen of this species, collected by J. Arechavaleta (MVM 2946), with “Plantas de la República del Uruguay [Plants from the Republic of Uruguay]” printed on the label, and only “Febrero [February] 1907” written by hand. Nonetheless, given the scarce information provided on the label (e.g. there is no information about locality), and the lack of new records supporting the presence of this species in the country, we are not including T. lorentziana in the flora of Uruguay.

It should be noticed that T. lorentziana is a widely distributed species that has been collected in the state of Rio Grande do Sul ( Brazil), in an area very proximate to the border with Uruguay. Hence, we do not completely discard the possibility of this species appearing in future samplings.

Excluded entities from the Uruguayan flora

Tillandsia crocata (É. Morren) N.E. Brown (1882: 1015) ≡ Phytarrhiza crocata É. Morren (1880b: 87) . Type (lectotype designated by Smith 1935: 183):—[Icon] Morren Icon No.70 (K!).

Tillandsia crocata was originally cited for Uruguay by Smith (1933) based on the specimen Osten 3055 (MVM). Then, Marchesi (1965) expanded the distribution adding several new specimens, as did Smith (1972). Nonetheless, we analyzed the specimens from Uruguay identified as T. crocata and concluded that all of them belong to T. myosura (see Note I of T. myosura ).

Tillandsia streptocarpa Baker (1887: 241) .Type (lectotype designated by Smith &Downs 1977:858 [as “ holotype ”]):— PARAGUAY. [Central]: Luque, “Croissant sur les branches du Lapacho”, August 1876, Balansa 615 (K000321881 [online image!]; isolectotypes: BR0000008846143 [online image!], GOET000457 [online image!], LE00006309 [image!], P00438676 [online image!], P00438677 [online image!], S-R-6155 [online image!]).

Herter (1930) reported Tillandsia streptocarpa for Uruguay without specifying the locality or providing reference to herbarium material. Further, there are no subsequent records corroborating the presence of this species in the country. Considering the distinctive characteristics of the species, such as large clumps and showy flowers, it seems highly improbable that the species, if present in the country, would have gone unnoticed and uncollected.

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 46. Tillandsia xiphioides. A. Habitat; Sierra de Mahoma (San José, Uruguay). B. Habitat; ca. Paso Pereira (Cerro Largo, Uruguay). C. Habit (Sierra de Mahoma). D. Close up of a shoot with inflorescence. E. Detail of the fertile part of the inflorescence in pre-anthesis. F. Inflorescence. G. Lateral view of the flower. H. Front view of the flower. I. Capsule basally clasped by the sepals and the floral bract. Photos by Andrés Rossado.

FIGURE 47. Distribution map of Tillandsia xiphioides in Uruguay and neighboring areas.