Tillandsia stricta Solander ex Ker Gawler (1813

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

13. Tillandsia stricta Solander ex Ker Gawler (1813 : t. 1529). Figs. 5D , 36 , and 37.

≡ Anoplophytum strictum (Sol. ex Ker Gawl.) Beer ([1856] 1857: 39). Type (lectotype, first-step designated by Smith & Downs 1977: 824 [as “type”]):— BRAZIL. [Rio de Janeiro]: Rio de Janeiro, 13 November–7 December 1768, Banks & Solander s.n. ( BM [two specimens], second-step lectotype designated here: BM000923935 [online image!]; syntype: BM000923934 [online image!]) .

Plants acaulescent or short-stemmed, mainly not branched or sometimes few-branched from the base and then forming clumps up to 20 cm in diameter. Roots 0.5–0.8 mm diameter, only present at the base of the stem. Stems up to 5 cm long. Leaves spirally arranged, clustered forming a rosette, mostly green with the basal portion whitish or grayish, occasionally completely grayish, or sometimes with purple spots or completely violaceous when sun-exposed; sheaths 6–15 mm wide, hardly differentiated from the blade, glabrous at the base then densely lepidote; blades (60–)80–185 × 6–13 mm, suberect to spreading, very narrowly triangular, channelled from the base to almost the apex, chartaceous, densely subappressed-lepidote at least basally, generally appressed-lepidote towards the apex, trichomes asymmetric at the base of the adaxial face and symmetric on the rest of the blade. Inflorescences simple; peduncles wholly covered by bracts or sometimes apically exposed, 6.5–11(–15) cm long, 2–3.5 mm in diameter, totally glabrous or sometimes with few trichomes only present near bract insertions; peduncle bracts 5 to 12 in number (the basal ones leaf-like), erect to suberect, evenly distributed along the peduncle, densely imbricate (sheaths covering at least the basal portion of the sheath of the following bract); upper peduncle bract with developed blade; sheath 12–20 × 7–12 mm, elliptic to ovate, pink, densely lepidote throughout; blade 10–35(–45) mm long. Spike spirally and densely 8 to 22(28)-flowered, 27–75 mm long, generally ellipsoid; rachis partially exposed, light green to pink, glabrous, sometimes with few trichomes only present near the insertion of the floral bracts. Floral bracts densely distributed [(1.5)3.5–8 times longer than the internodes], laxly imbricate, ecarinate; sheath inflated, elliptic to elliptic-ovate, pink to fuchsia; basal floral bracts always with blade; sheath 11–21 × 9–14 mm, longer than the sepals and even surpassing all or most of the flower, sparsely lepidote to densely lepidote throughout, generally trichomes denser towards the apical half, sometimes with trichomes only present in the apical half; blade 2–32 mm long; upper floral bracts shorter, bladeless, trichomes present towards the apex, or sometimes sparsely distributed throughout, or altogether lacking. Flowers 15–22 mm long, scentless; sepals (7–)8–12 × 2.4–4.4 mm, evenly very short connate at the base for 1.5–3 mm, narrowly elliptic to narrowly elliptic-ovate, whitish to pinkish, glabrous; abaxial sepal ecarinate; adaxial sepals slightly carinate, and generally a little longer and wider than the abaxial one; petals (12–)14–24 × 2.6–3.9 mm, lingulate, basal half white with the base semitransparent, apical half lilac; distal portion suberect to divergent, rarely spreading, margins entire or slightly irregular; stamens 8–15 mm long, included and visible (reaching the throat of the corolla), shorter than the pistil; filaments 7–13 mm long, plicate for less than 2 mm about the middle; pollen yellow; pistil 10–18 mm long, included (reaching the throat of the corolla) or slightly exserted; ovary 2.2–3.2 × 1.5–2.1 mm, obovoid, clearly differentiated from the style; style 8–15 mm long, 3.2–5.5 times as long as the ovary, white; stigmas simple-erect, sometimes with stigmatic branches apically divergent. Capsules (23–)26–41 × 1.9–3.3 mm, much exceeding its respective floral bract, cylindrical-prismatic, apex rounded and short-beaked.

Vernacular name:— Clavel del aire, Clavel rosa (Brito & Llano 2018).

Classification:— Tillandsia stricta is the type species of T. subg. Anoplophytum ( Smith & Downs 1977) . Several infraspecific entities have been described for T. stricta . The taxon occurring in Uruguay and neighboring areas corresponds to the typical subspecies and variety.

Distribution and habitat:— Venezuela, Trinidad, Guyana, Surinam, Brazil, Paraguay, Argentina, and Uruguay. Tillandsia stricta is one of the most common and widely distributed species of Tillandsia in Brazil, where it grows as epiphyte and epilithic in a variety of habitats, including urban areas. In Argentina, this species is confined to the northeastern provinces of Misiones and Corrientes, and marginally in northern Santa Fe ( Pensiero et al. 2021).

In Uruguay, Tillandsia stricta is restricted to the east (Cerro Largo, Treinta y Tres, and Rocha departments; Fig. 37 ), where it occurs exclusively as epiphyte in some woodlands associated with the Laguna Merín basin. This species grows in partially shaded conditions inside riverside and moist hillside forests, together with T. aëranthos and T. geminiflora . Occasionally, it is also found growing at full sun. It should be noted that northern Rocha, in Uruguay, represents the southern limit of distribution of this widespread species ( Fig. 37 ).

Phenology:— In Uruguay, Tillandsia stricta flowers from late spring to early summer (peak blooming from December to early January; Fig. 4 ). Fruits begin to develop as of December–January and continue to grow in length until January or February. Afterward, they remain without apparent growth until seed dispersal, which takes place in autumn and winter (April to July). The complete reproductive cycle, from the onset of development of the inflorescence to the dehiscence of its capsules, takes approximately from five to eight months.

It should be noted that the time required for the inflorescence development in Tillandsia stricta is quite short, taking approximately 15 days. This is in sharp contrast to the time required by the rest of Tillandsia species found in Uruguay, which ranges from one to several months ( Fig. 4 ).

Reproductive observations:— The inflorescences of Tillandsia stricta have several flowers open at the same time ( Fig. 36C ). Each inflorescence remains in flower for a period of seven to 10 days. When the flowers wither, the petals darken, changing their color from lilac to purple-vinaceous. In T. stricta , the inflorescences are green at the beginning, gradually turning pink during their development. After the flowering period, the color of the peduncle, bracts, and sepals changes from pink to green, and they remain green and alive for several months (during fruiting time; Fig. 36H ). According to Machado & Semir (2006), this species is pollinated by hummingbirds, which agrees with our own observations made in Uruguay.

Conservation:— We consider Tillandsia stricta as Not Threatened in Uruguay. So far, few populations of this species have been registered within the country, most of them characterized by a high number of individuals inhabiting relatively well-preserved habitats. Tillandsia stricta occurs in the national protected area: ‘Paisaje Protegido Paso Centurión y Sierra de Ríos’ in the eastern part of the country and has also been observed growing in disturbed habitats. Additionally, it is highly probable that unregistered populations occur in less explored woodlands of the Laguna Merín basin, where suitable habitats for this species exist. It should be noted that T. stricta is considered as a priority for conservation in Uruguay by Marchesi et al. (2013).

Diagnostic characters:— In Uruguay, Tillandsia stricta is the only species of Tillandsia that combines spirally arranged flowers and sepals evenlY connate for at least ⅙ of its length (i.e. 1.5–3 mm). In the other species of Tillandsia occurring in Uruguay with spirally arranged flowers, the sepals are either unequally connate or equally connate for less than ⅒ of their length (i.e. 0.2–1.1 mm; Fig. 5A–E ).

Nevertheless, Tillandsia stricta is frequently confused with the sympatric species T. aëranthos , especially in pre or post-anthesis stages. In addition to the reproductive characters provided in the identification key, T. stricta can be differentiated from T. aëranthos by its leaf indument. Specifically, T. stricta has spreading trichomes at the base of the leaf blade and generally appressed trichomes towards the apex. This gives the basal portion of the plant a whitishgrayish appearance, contrasting with the greenish color of the rest of it. On the other hand, T. aëranthos has appressed trichomes throughout the blade, resulting in a uniformly colored plant.

Tillandsia stricta could also be confused with T. recurvifolia . However, these species do not overlap on their distribution (for morphological differences between these species, see “Diagnostic characters” of T. recurvifolia ).

Background in Uruguay:— Tillandsia stricta was cited for the first time for Uruguay in 1972 by Smith (1972), despite the existence of collections for the country since 1902 (e.g. Berro 2417).

Note I: —In the original publication, reference is made to plant material by Banks and Solander (i.e. “Soland. Mss. In Sched. Banks.”) and also to an illustration (i.e. “Fig. pict. In icon pl. brasil. In Cod. Banks.”). At BM, the herbarium where Banks and Solander’s materials are hosted, there are two specimens collected by them (BM000923934 and BM000923935) that bear labels that read “ Tillandsia stricta ” and whose characteristics perfectly match those of the protologue. Smith & Downs (1977) cited Solander & Banks (BM) as the “type” material for T. stricta but without specifying which of the two sheets they had selected. Thus, we consider this a first-step lectotypification, and therefore here we designate BM000923935 as the lectotype of Tillandsia stricta , thus performing a second-step lectotypification. BM000923935 has abundant plant material and is the only type specimen that preserves petals, a diagnostic character in this group.

Note II:— The authorship of Tillandsia stricta has been ascribed to John Sims by Smith & Downs (1977). However, the actual author was Ker-Gawler, as indicated with the “G’ written at the end of the article ( Weber 1982), and not Sims, who was the editor of the Curtis’s Botanical Magazine the year that T. stricta was published.

Representative specimens examined:— URUGUAY. Cerro Largo: Sierra de los Ríos , 5 December 1996, Bayce & Grela s.n. ( MVFA 26245 b) . Rocha: Río Cebollatí , campo de Benke, 13 January 1989, Marchesi et al. s.n. ( MVFA 19368 ) . Treinta y Tres: Vergara , 7 January 1980, Brescia et al. s.n. ( MVFA 16505 ) .

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 36. Tillandsia stricta. A. Habit; fruiting plant (Cebollatí River, Rocha, Uruguay). B. Habit; flowering plant (Tacuarí River, Treinta y Tres, Uruguay) C. Inflorescences. D. Close up of the fertile part of the inflorescence. E. Front view of the flowers. F. Lateral view of the flower with its floral bract. G. Capsule. H. Infructescence. Photos by Andrés Rossado.

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