Tillandsia × marchesii Rossado, 2024

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

9. Tillandsia × marchesii Rossado , nothosp. nov. [ Tillandsia aëranthos (Loisel.) L.B. Smith × T. recurvifolia Hooker ].

Figs. 5C , 27 , and 29.

Diagnosis:— Intermediate in morphology between Tillandsia aëranthos and T. recurvifolia , but it is distinguished from both and other sympatric taxa by a combination of the following characters: generally caulescent plants, leaves appressed-lepidote at least towards the apex, inflorescences simple with spirally arranged flowers, upper floral bracts densely to subdensely lepidote in the apical portion, flowers surpassing the sheath of their respective floral bract, sepals lepidote and unequally connate, petals lilac to light purple.

Type: — URUGUAY. Artigas: Arrocera RIUSA, San Gregorio (ca. Aº Mandiyú ), 30°32’S, 57°42’W, 26–27 September 2014 (cultivated in Montevideo, pressed 30 October 2016; fl.) , A. Rossado 463 (holotype: MVFA!).

Plants caulescent or nearly acaulescent, not branched to few-branched. Roots 0.5–0.8 mm in diameter, only present at the base of the stem. Stems up to 12 cm long. Leaves spirally arranged, distributed along the stem, grayish-green to greenish; sheaths 7–18 mm wide, hardly differentiated from the blade, densely lepidote, except for the glabrous basal portion; blades 40–110 × 6–10 mm, erect to spreading, very narrowly to narrowly triangular, channelled except for the apex, chartaceous, densely appressed-lepidote throughout, but sometimes subappressed trichomes on basal portion, trichomes mostly symmetric. Inflorescences simple; peduncles wholly covered by bracts or seldom apically visible, 5–9 cm long, glabrous; peduncle bracts 5 to 10 in number (the basal ones leaf-like), erect, clasping the peduncle, evenly distributed along the peduncle, densely imbricate; upper peduncle bract with developed blade; sheath 20–30 × 8–12 mm, elliptic-ovate, pink to fuchsia, lepidote with denser trichomes towards the apex or trichomes only present in the apical portion; blade 8–14 mm long. Spike spirally and densely 7 to 11-flowered, 3–6.5 cm long, ellipsoid; rachis hidden by the floral bracts or sometimes partially exposed, pinkish, glabrous. Floral bracts densely to very densely distributed, imbricate or not, ecarinate; sheath clasping the base of the flowers, elliptic to elliptic-ovate, pink to fuchsia; basal floral bracts always with blade; sheath 17–26 × 9–16 mm, longer than the sepals, trichomes present generally in the apical half but sometimes distributed from the base to the apex or only present in the apical fourth; blades 3–15 mm long; upper floral bracts shorter, bladeless, densely to subdensely lepidote towards the apex. Flowers 20–29 mm long, scentless; sepals mostly hidden by floral bracts, 14–18 × 5–7 mm, unequally connate to nearly evenly connate, narrowly elliptic-ovate to narrowly ovate, pinkish, trichomes towards the apex and sometimes also along the carena; abaxial sepal ecarinate, connate with the adaxial sepals for 0.2–0.5 mm (appearing free); adaxial sepals (strongly) carinate, connate to each other for 0.5–13.5 mm (extremely variable among individuals), and longer than the abaxial one; petals 23–26 mm long, spatulate; claw 2–2.5 mm wide, basally semitransparent, apically white; limb 3.5–5 mm wide, spreading, elliptic, lilac to light purple, margins slightly irregular to entire; stamens 14–18 mm long, included and visible, about equaling the pistil; filaments 10–14 mm long, plicate for ca. 1 mm in the apical half (sometimes barely noticeable); pollen yellow; pistil 13–15 mm long, included; ovary 4–4.5 × 2.3–3.3 mm, globose-obovoid, apex obtuse, clearly differentiated from the style; style ca. 9 mm long, ca. 2–2.5 times as long as the ovary, white; stigmas simple-erect. Capsules not seen.

Etymology:— The specific epithet honors the botanist Eduardo H. Marchesi, for his great contributions to the flora of Uruguay.

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

Distribution and habitat: — Argentina and Uruguay ( Fig. 29 ). Tillandsia × marchesii has been recorded only in two localities to date: one in north-western Uruguay, in Artigas department, where it is relatively common on the open thorn forest associated to the Mandiyú River, and the other in an open thorn forest associated to the Miriñay River in southern Corrientes province, Argentina. However, as this taxon is likely of hybrid origin between T. aëranthos and T. recurvifolia , it is to be expected wherever populations of these two species occur sympatrically and with an overlapping blooming period.

Tillandsia × marchesii grows exclusively as epiphyte in open thorn forests together with T. aëranthos , T. bandensis , T. duratii , T. ixioides , T. recurvata , and T. recurvifolia .

Phenology:— Flowers have been recorded in July, September, and October, similar to the phenology of its parental species.

Conservation:— Not applicable.

Diagnostic characters:— Tillandsia × marchesii has intermediate characteristics between T. aëranthos and T. recurvifolia ( Table 2). This hybrid shares with its parents the presence of leaves and flowers spirally arranged, floral bracts pink to fuchsia, flowers scentless, adaxial sepals carinate, petals spatulate, stamens and pistil included, filaments plicate, and pistil longer than the ovary.

Tillandsia × marchesii differs from T. aëranthos by its sepals lepidote (vs. glabrous), the adaxial ones generally connate for less than ⅔ of their length (vs. more than ⅔ of their length), petals up to 5 mm wide (vs. 5–8 mm), and upper floral bracts with dense trichomes towards the apex (vs. glabrous or occasionally provided with scarce trichomes at the apex). Moreover, in the area of occurrence of T. × marchesii , the individuals of T. aëranthos have green leaves and dark purple petals, while in the hybrid the leaves are gray-greenish, and the petals lilac or light purple ( Fig. 27C ). In addition, in some hybrid individuals the trichomes at the base of the leaf blade are subappressed, while in T. aëranthos the trichomes are clearly appressed throughout the blade.

Tillandsia × marchesii differs from T. recurvifolia by having longer flowers that clearly surpass the sheath of its respective floral bract (vs. basal flowers not surpassing or equaling the sheath of the floral bract; Fig. 27C ), sepals unequally connate (vs. evenly connate), petals lilac to light purple (vs. white; Fig. 27C ), and trichomes of the floral bracts with the wing appressed and finely dentate (vs. divergent and strongly dentate wing; Fig. 28 , and compare Fig. 27D with Fig. 34E ). Moreover, most of the hybrid individuals are caulescent with leaves distributed along the stem (vs. acaulescent or if caulescent then leaves grouped apically) and have appressed trichomes at least in the middle and apical portion of the leaf limb (vs. subappressed trichomes all along).

It should be noted that because of the likely hybrid nature of this entity, some characteristics are highly variable among individuals. This is especially notable in the indument of the leaves, and in the length of the connate portion between adaxial sepals ( Fig. 27F–G ).

Note I:— The hybrid nature of Tillandsia × marchesii is supported by morphological characters intermediate between the two presumed parental taxa ( Table 2; Fig. 27C ). Additionally, the hybrid is only found where populations of T. aëranthos and T. recurvifolia overlap. These suspected parental species share hummingbirds as pollinators ( Bianchi & Vesprini 2014; Gomes et al. 2020; and personal observations), and in the areas where this hybrid was recorded, they have a synchronous phenology.

In northwestern Uruguay, in Artigas department ( Uruguay), where several hybrid specimens were found in a relatively small area, T. aëranthos and T. recurvifolia are extremely common species, but they mostly inhabit slightly different forests. In this sense, T. recurvifolia is more frequent in the open forest, and T. aëranthos in areas where the forest is a little denser. Nevertheless, both types of forests are very close to each other, and occasionally, individuals of both species are found growing on the same tree. Considering all the facts mentioned above, it is not surprising that hybridization occurs between these two species.

Note II:— It should be noted that in the areas where Tillandsia × marchesii is distributed, another species with spirally arranged flowers occurs: T. ixioides . Nonetheless, this species is disregarded as a putative parental species since several morphological typical characteristics of T. ixioides (e.g. rigid leaves, fragrant flowers, conspicuous pedicels, yellow petals, chartaceous floral bracts, straight filaments) are not present in T. × marchesii , not even as an intermediate character. Furthermore, in the area where this hybrid occurs, T. ixioides generally flowers somewhat earlier than the other species of Tillandsia with spirally arranged flowers, and in addition, T. ixioides does not share pollinators with them.

Additional specimens examined (Paratypes):— ARGENTINA. Corrientes: Dpto. Paso de los Libres, Ruta nacional 14 a 1, 3 km al noreste del Río Miriñay , 29°57’35’’S, 57°40’25’’W, 26 September 2016, Rossado et al. 453 ( MVFA!) . URUGUAY. Artigas: Arrocera RIUSA, San Gregorio (ca. Aº Mandiyú ), 30°32’S, 54°27’31’’W, 27 September 2014 (cultivated in Montevideo, pressed 11 July 2015), Rossado 417 ( MVFA!) .

Figures

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 27. Tillandsia × marchesii. A. Habitat; open thorn forest near the Mandiyú River (Artigas, Uruguay); left: T. recurvifolia, right: T. × marchesii. B. Habit (near the Mandiyú River). C. Lateral view of the inflorescence; top: T. aëranthos; middle: T. × marchesii; bottom: T. recurvifolia. Notice that T. × marchesii shows intermediate characteristics between T. aëranthos and T. recurvifolia regarding trichome density of the floral bract, petal color and, in basal flowers, the relative length between the flower and its corresponding floral bract (taking into account solely the sheath portion of the floral bract).D. Close up of the apical part of the flower and its floral bract.Notice the presence of trichomes on sepals (typical of T. recurvifolia), and the presence of trichomes appressed and with nearly entire margins on the floral bract (typical of T. aëranthos). E. Front view of the flower. F. Lateral view of the flower with its floral bract partially removed. Notice the presence of highly connate adaxial sepals (typical of T. aëranthos) and the presence of trichomes on the sepals (typical of T. recurvifolia). G. Lateral view of the flower; here the adaxial sepals are connate although to a much lesser extent in proportion compared to the flower depicted in F. This highlights the significant variability present among individuals of hybrid entities. Photos by Andrés Rossado.

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 29. Distribution map of Tillandsia × marchesii.

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.