Tillandsia recurvifolia Hooker (1861

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

12. Tillandsia recurvifolia Hooker (1861 : t. 5246). Figs. 5E , 34 , and 35.

Type (lectotype designated by Till & Luther 1995: 265 [as “type”]):—[Icon] t. 5246 in Hooker (1861)!.

– Tillandsia meridionalis auct . non Baker (1888)

Plants acaulescent, not branched to few-branched from the base and then forming clumps up to 20 cm in diameter but generally smaller. Roots 0.5–0.8 mm diameter. Leaves spirally arranged, clustered forming a basal rosette, grayish; sheaths ca. 8–16 mm wide, hardly differentiated from the blade, glabrous at the base then densely lepidote; blades 40–90 × 8–14 mm, erect to spreading, generally turning secund, narrowly triangular, channelled from the base to almost the apex, chartaceous, densely subappressed-lepidote throughout, trichomes asymmetric. Inflorescences simple; peduncles wholly covered by bracts or sometimes apically exposed, 3.5–10 cm long, ca. 2.5 mm in diameter, glabrous; peduncle bracts 4 to 6 in number (the basal one leaf-like), erect to suberect, evenly distributed along the peduncle, generally imbricate (sheaths covering at least ¼ of the sheath of the following bract); upper peduncle bract with developed blade; sheath 15–35 × ca. 10–13 mm, elliptic-ovate, pink, subdensely to densely lepidote, sometimes sparsely lepidote towards the base; blade 9–20 mm long. Spike spirally and densely 6 to 12-flowered, 30–55 mm long,

1 Linnaeus (1753) likely erred when citing “t. 120” instead of “t. 121”, as the latter was cited for Renealmia recurvata in Linnaeus

(1762), and earlier in Royen (1740), work from which Linnaeus (1753) took the polynomial name for R. recurvata .

mainly ovoid-ellipsoid; rachis basally partially exposed, reddish-pink to reddish, glabrous or with scattered trichomes. Floral bracts densely distributed (4.5–7 times longer than the internodes), generally not imbricate, ecarinate; sheath inflated, elliptic to elliptic-ovate, pink; basal floral bracts always with blade; sheath 16–27 × 9–17 mm, longer than the flower, subdensely to densely lepidote, trichomes denser or concentrated towards the apex, sometimes sparsely lepidote towards the base; blade (1–) 3–12 mm long; upper floral bracts shorter, bladeless or with a very short blade, densely to subdensely lepidote but generally with the basal half glabrous. Flowers 12–22 mm long, scentless; sepals visible, 12–17 × 4.5–7 mm, evenly very short connate at the base for 0.3–1.1 mm, narrowly elliptic-ovate, sometimes narrowly elliptic, pinkish, with trichomes towards the apex; abaxial sepal ecarinate; adaxial sepals carinate (especially noticeable towards the apex), and generally slightly longer and wider than the abaxial one; petals 18–25 mm long, spatulate; claw ca. 2 mm wide, basally semitransparent, apically white; limb 3.4–5 mm wide, mainly spreading, elliptic, white, margins entire or slightly irregular; stamens 12–18 mm long, included and visible (reaching the throat of the corolla), equaling or shortly exceeding the pistil; filaments 8–14 mm long, plicate for less than 2 mm in the apical half; pollen yellow; pistil 10–16 mm long, included (reaching the throat of the corolla), not visible; ovary 2.9–5 × 2.3–3.3 mm, globose-obovoid or short ellipsoid-obovoid, clearly differentiated from the style; style 7.5–10.5 mm long, 1.9–2.7 times as long as the ovary, white; stigmas simple-erect. Capsules (24–)29–36 × 3.8–4.1 mm, much exceeding its respective floral bract, cylindrical-prismatic, apex obtuse and short-beaked.

Vernacular names:— Not known. Possibly clavel del aire.

Classification:— Based on its morphological characteristics, Tillandsia recurvifolia belongs to T. subg. Anoplophytum s.s. ( Smith & Downs 1977, as T. meridionalis ).

Distribution and habitat: — Bolivia, Paraguay, Brazil, Argentina, and Uruguay. In Brazil, Tillandsia recurvifolia occurs only in a few localities of the southern states. In Argentina, it is a widespread and common species, occurring from north to central Argentina (Jujuy and Misiones to Entre Ríos provinces), where it grows mainly as epiphyte in open woody vegetation (Chaco and Espinal phytogeographic provinces).

In Uruguay, Tillandsia recurvifolia has a restricted distribution, as it is only known from a few localities in Artigas and Salto departments ( Fig. 35 ), in areas influenced by the Espinal phytogeographic province. There, it grows exclusively as epiphyte in open thorn forests, cohabiting with other species of Tillandsia such as T. aëranthos , T. bandensis , T. duratii , T. ixioides , and T. recurvata , as well as with some epiphytic cacti. Although its distribution in the country is restricted, in some areas it is very abundant, especially in those with more xeric forests, where it can even be the dominant species of the epiphytic community.

Phenology:— In Uruguay, Tillandsia recurvifolia flowers from late winter to early spring (with peak blooming throughout September and October; Fig. 4 ). Fruits begin to develop mostly as of October and they continue to grow in length for about one month. Then they remain without growth until seed dispersal between late spring and early summer (mostly in December and January). The complete reproductive cycle (from the onset of the inflorescence emergence to the dehiscence of the capsules) takes approximately five months. It should be noted that in Uruguay the phenology of T. recurvifolia is very similar to that of T. aëranthos (the most common Tillandsia species in Uruguay).

Reproductive observations:— The inflorescences in Tillandsia recurvifolia have several flowers open simultaneously ( Fig. 34B ). Individual flowers remain open for five to seven days, consistent with what has been reported from Argentina ( Bianchi & Vesprini 2014). The bracts are initially green-pinkish during inflorescence emergence, turning pink well before the first flower opens. After the flowering period, the floral bracts dry up, while the peduncle and sepals change their color from pink to green, remaining alive during fruiting time ( Fig. 34G ).

According to Bianchi & Vesprini (2014) and Gomes et al. (2020), Tillandsia recurvifolia is a self-incompatible species whose flowers are pollinated by both hummingbirds and butterflies, something also confirmed by our own observations ( Fig. 34C ).

Conservation:— We consider Tillandsia recurvifolia as Threatened in Uruguay. The species is limited to a few populations within the country ( Fig. 35 ), all occurring in open thorn forests. This habitat has undergone fragmentation and is currently threatened by agricultural activities and logging. Furthermore, none of these populations are located in protected areas. Given these facts, despite being locally abundant, T. recurvifolia could face extinction in Uruguay if appropriate environmental protection actions are not implemented. It should be noted that this species is considered as a priority for conservation in Uruguay by Marchesi et al. (2013).

Diagnostic characters:— In Uruguay, Tillandsia recurvifolia could be confused with T. aëranthos and T. stricta . The former is easily distinguished from both species by having sepals with trichomes towards the apex (vs. wholly glabrous), and trichomes on the floral bracts with margins deeply and conspicuously dentate (vs. finely dentate, sometimes appearing entire; Fig. 28 ). Additionally, T. recurvifolia has white petals contrasting with the blue or lilac petals of T. aëranthos and T. stricta . However, caution is advised when considering this character, as we have found rare individuals of T. aëranthos with partially or totally white petals.

Tillandsia recurvifolia can also be differentiated from the sympatric species T. aëranthos by its basal flowers, which are shorter or of equal length to that of the sheath of its respective floral bract (vs. considerably longer, usually much longer). AdditionallY, sepals are evenlY connate bY less than ⅒ of their length (vs. adaxial sepals connate to each other bY about ⅔ of their length, abaxial sepal nearlY free), and trichomes from the leaf blade have spreading wings (vs. appressed). However, it is important to note that in Uruguay, T. aëranthos and T. recurvifolia hybridize frequently (see T. × marchesii ).

Tillandsia recurvifolia and T. stricta do not overlap their distribution within Uruguay ( Figs. 35 and 37 ), and they inhabit different vegetation types. The former develops in open and dry forests, while the latter occurs in denser and more humid ones. Tillandsia recurvifolia clearly differs from T. stricta by having sepals 4.5–7 mm wide and connate bY less than ⅒ of their length (sometimes appearing free), while in T. stricta , these are 2.4–4.4 mm wide, and connate bY at least ⅙ of their length ( Fig. 5D–E ).

Background in Uruguay:— Although Tillandsia recurvifolia has been collected from Uruguay since 1958 (Klappenbach s.n.), the species was not formally cited for the country until 2008 by Brito & Llano. However, its presence in Uruguay was noted as probable by Smith (1972) under the misapplied name T. meridionalis .

Note I:— Tillandsia recurvifolia is a name that has bewildered taxonomists throughout the years ( Weber 1982; Till & Luther 1995). The reason for this is partly because there is no type specimen of T. recurvifolia preserved for examination (as indicated earlier, the type of this name is an illustration), but mostly due to the confusing locality information cited in its original description.

In the protologue of T. recurvifolia, W.J. Hooker stated that the species was introduced to Kew Gardens by W.D. Christie from Panama. This locality citation is puzzling because there are no Tillandsia species known to Panama that resemble T. recurvifolia . Weber (1982), based on the examination of other gatherings, concluded that Christie never collected plants in Panama, but he did in Paraná (via J. E. Gibert), as this locality is written on the labels of several of Christie’s specimens (e.g. K000486885, K000828217, K000976097). Since these specimens have no reference to a country, “ Paraná ” could be interpreted as the Brazilian state, the Paraná River ( Brazil, Paraguay, and Argentina), or the city in Argentina. Nevertheless, in a letter from Christie to Hooker dated February 23, 1859, Christie noted “Paraná is on the river Paraná, opposite Santa Fe ”, and in another letter from Buenos Aires to the Royal Botanical Garden, dated October 27, 1958, Christie wrote “Paraná is the capital of Entre Ríos. Its name on any old map is Bajada.” Based on this information, the city of Paraná in the province of Entre Ríos in Argentina should be considered as the place of origin of the plant upon which Hooker based his description and not Panama (this is important to note as several specimens of Christie have been erroneously ascribed to Paraná state in Brazil). According to Weber (1982), in Hooker’s time there were no typewriters, and Hooker’s handwritten manuscript was possibly the cause of this distortion by the typesetter.

In the area around Paraná in Entre Ríos ( Argentina), besides Tillandsia recurvifolia there is no other species of Tillandsia that matches the illustration and description given in the protologue for this species (e.g. spirally arranged flowers with white petals, basal flowers not surpassing the sheath portion of the bract, sepals evenly connate). Earlier authors ( Castellanos 1945; Smith 1972; Smith & Downs 1977; Zuloaga et al. 2019) considered specimens from this area with the characteristics mentioned above as T. meridionalis , albeit not in the sense of Baker (1888). Tillandsia meridionalis is currently considered a synonym of T. ixioides (see Note V of T. ixioides ). Therefore, and in accordance with the proposal of Till & Luther (1995), the correct name of the entity previously identified as T. meridionalis auct . non Baker is T. recurvifolia .

Note II:— It is worth mentioning that, although Tillandsia recurvifolia was inadvertently lectotypified by Till & Luther (1995) using the illustration in Hooker (1861), the idea of using the illustration as the type was initially suggested by Weber (1982).

Representative specimens examined:— URUGUAY. Artigas: RIUSA - Cercanías de Aº Mandiyú , 26 September 2014, Rossado et al. 366 ( MVJB) . Salto: Costa del Espinillar , October 1958, Klappenbach s.n. ( MVM 2948 ) .

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 5. Illustrations of floral parts. A. Tillandsia aëranthos. B. T. ixioides. C. T. × marchesii. D. T. stricta. E. T. recurvifolia. F. T.geminiflora. From left to right: floral bract (stretched view), sepals (stretched view; adaxial sepals to the right), petal (stretched view), and pistil.A based on Rossado et al. 29 (MVFA; floral bract and sepals) and Haretche 807 (MVFA; petal and pistil); B based on Rossado et al. 455 (MVFA); C based on Rossado 463 (MVFA); D based on Rossado et al. 200 (MVFA; floral bract, petal and pistil) and Rossado 412 (MVJB; sepals); E based on Rossado et al. 366 (MVJB); F based on Rossado 17 (MVFA; floral bract, petal, and pistil) and MVFA 440 (sepals).

FIGURE 28. Illustrations of trichomes from the floral bracts. A. Tillandsia aëranthos (Rossado 190). B. T. × marchesii (Rossado 463). C. T. recurvifolia (Rossado et al. 452). Drawn by Andrés Rossado.

FIGURE 34. Tillandsia recurvifolia.A. Habitat; open thorn forest near the Mandiyú River (Artigas, Uruguay). B. Habit; plant in bloom (near the Miriñay River, Corrientes, Argentina). C. Close up of the fertile part of the inflorescence with a butterfly visiting the flowers (near the Mandiyú River). D. Lateral view of the flower with its floral bract. E. Detail of the trichomes of the floral bract. F. Front view of the flower. G. Capsule. H. Plant releasing seeds (near the Mandiyú River). Photos by Andrés Rossado.

FIGURE 35. Distribution map of Tillandsia recurvifolia in Uruguay and neighboring areas.

FIGURE 37. Distribution map of Tillandsia stricta in Uruguay and neighboring areas.