Tillandsia duratii Visiani (1840a: 23

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

5. Tillandsia duratii Visiani (1840a: 23 [= 1840b: 271]). Figs. 12C , 19 , and 20.

≡ Phytarrhiza duratii (Vis.) Visiani (1854: 7 [= 1855: 341]) ≡ Anoplophytum duratii (Vis.) Beer ([1856] 1857: 42). Type (lectotype designated here):—Without locality: s.d., Visiani s.n. (PAD [H0061569, digital image!])

= Tillandsia circinalis Grisebach (1874: 272) ≡ Phytarrhiza circinalis (Griseb.) É. Morren (1879: 370) .Type (lectotype, first-step designated by Smith & Downs 1977: 860 [as “type”]):— ARGENTINA. Córdoba: Sierra de Córdoba, near La Calera, “Am Baumaesten auf Huegeln bei der Calera (vorberge Sierra von Córdoba)”, September 1871, Lorentz 512 (second-step lectotype designated here: GOET000430 [online image!]; isolectotypes: B10 0243338 [online image!], CORD00004745 [digital image!]).

Plants caulescent, not branched or generally branched and then forming subdense clumps up to 35 cm in diameter. Roots up to 1 mm in diameter, present at the base of the stem but usually absent in adult plants. Stems up to 50 cm long but generally shorter. Leaves spirally arranged, distributed along the upper part of the stem, gray; sheaths 34–50 × 30–35 mm, clearly distinct from the blade, widely elliptic, basal half glabrous, apical half densely lepidote; blades (9–)15–30 × 0.8–2 cm, mainly reflexed, sometimes spreading, very narrowly triangular, channelled from the base to the middle or almost the apex, fleshy, densely tomentose-lepidote throughout, trichomes asymmetric, apex generally spirally recurved. Inflorescences compound, 1 to 2-branched; peduncles wholly covered by bracts, 8–45 cm long, 2.4–4.5 mm in diameter, glabrous or with trichomes only present near bract insertions; peduncle bracts 5 to 9 in number (the basal ones life-like), erect, evenly distributed along the peduncle, densely imbricate; upper peduncle bract bladeless, 40–75 × 14–18 mm, narrowly elliptic to elliptic-ovate, grayish to grayish-green, sometimes stramineous towards the apex, densely lepidote. Inflorescence fertile part 5–36 cm long, very narrowly ellipsoid; axis 3–32 cm long, mostly hidden by bracts and branches, straight; branches 2 to 13 in number, spirally arranged, erect to suberect; primary bracts like the upper peduncle bracts, clasping the base of the branches; primary peduncles 8–90 mm long, with 1 to several sterile bracts; spikes distichously and densely 2 to 9-flowered, 15–50 mm long, complanate, very narrowly elliptic in outline; rachis mostly hidden by the floral bracts and flowers, green to vinaceous, subdensely lepidote or with trichomes only present near the insertion of the floral bract. Floral bracts 10–17(–19) × 5–8 mm, shorter or sometomes equaling the sepals, densely distributed (3–5 times longer than the internodes), imbricate, clasping the basal half of the flower, bladeless, ovate to elliptic-ovate, or elliptic-oblong, ecarinate, grayish-stramineous, sometimes basally grayish-green or gray-purplish, subdensely to densely lepidote, rarely subglabrous. Flowers 15–25 mm long, strongly fragrant; sepals partially visible to not visible, 10–15 × 5–6.5 mm, evenly short connate at the base for 1–2 mm, elliptic to elliptic-obovate, ecarinate, greenish to brownish, sometimes reddish towards the apex, glabrous or sometimes with scattered trichomes; petals 23–30 mm long, spatulate; claw ca. 2–3 mm wide, basally semitransparent, apically white; limb 10–18 mm wide, spreading to slightly reflexed, widely obovate, lilac and generally with darker lilac spots, basally white, margins crenulate; stamens 9–13 mm long, included, longer than the pistil; filaments 6–10 mm long, straight (not plicate); pollen yellowish-orange; pistil 5–6.5 mm long, deeply included; ovary 2.5–4 × 1.3–2 mm, cylindrical, tapering into the style; style 1.5–3 mm long, shorter than the ovary, white; stigmas simple-truncate. Capsules 32–47 × 2.5–3.5 mm, much exceeding its respective floral bract, cylindrical-prismatic, apex acute and short-beaked.

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

Classification:— Tillandsia duratii is the type species of T. subg. Phytarrhiza s.s ( Barfuss et al. 2016).

Distribution and habitat:— Bolivia, Paraguay, Brazil, Argentina, and Uruguay. In Brazil, Tillandsia duratii is mainly distributed in the central western dry woods (Goiás, Mato Grosso, Mato Grosso do Sul) while in southern Brazil, the species distribution is restricted to Rio Grande do Sul state where it is only reported for two sites close to Uruguay (“Parque Estadual do Espinilho” and Jarau Hill; Fig. 20 ). In Argentina, T. duratii is a common species, widely distributed from northern to central Argentina, mainly inhabiting dry open woods of the Chaco, Monte and Espinal phytogeographic provinces or other habitats influenced by them.

In Uruguay, T. duratii is restricted to the northwest of the country (Artigas, Salto and Paysandú departments; Fig. 20 ), inhabiting open thorn forests associated to the Uruguay River and some of its tributaries. There, T. duratii forms subdense, grayish clumps that grow exclusively as epiphytes, mainly on branches of spiny legume trees, generally almost fully sun-exposed ( Fig. 19A ). Furthermore, it is found growing on the top of large trees in the riverside forest of the Uruguay River.

Phenology: —In northern Uruguay, Tillandsia duratii flowers from mid-winter to mid-spring (mainly August, September, and October; Fig. 4 ). The inflorescences begin to develop in summer, and it takes several months until the first flower opens. Plants with unopened fruits were observed as of September-October, and seed dispersal in winter. In each plant a period of approximately one and a half years occurs between the beginning of inflorescence emergence and the dehiscence of capsules, representing one of the longest reproductive cycles recorded for Tillandsia in Uruguay.

Reproductive observations:— Tillandsia duratii has large and branched inflorescences that bear a high number of flowers, several of which are open at the same time. These flowers emit an intense and sweet odour, especially notorious at dusk.According to Gomes et al. (2020), T. duratii is a self-compatible species, whose flowers are open for approximately three days and are mainly pollinated by moths (non-hawk moths) and bees.

Conservation:— We consider Tillandsia duratii as Threatened in Uruguay, not only due to its restricted distribution but also because most of its populations occur in open thorn forests, a habitat that has experienced fragmentation and is currently threatened by agricultural activities and logging. Additionally, none of these populations occurs in national protected areas. It is also worth mentioning that this species is highly valued as an ornamental plant and is usually collected from its natural habitat for horticultural trade or by enthusiasts. Due to these significant threats, we consider this species as a priority for conservation in Uruguay, in disagreement with Marchesi et al. (2013).

Diagnostic characters:— Tillandsia duratii is a highly distinctive species with no morphologically close species present in Uruguay. This species is easily recognizable, even in the absence of reproductive structures, as it is the only Tillandsia in the country with leaf apex generally spirally recurved, often entwining around small branches. Additionally, it is the only species with compound inflorescences and fleshy leaves.

Background in Uruguay:— Tillandsia duratii was initially mentioned for the Uruguayan flora by André in 1905, although without specifying any reference material. Subsequent works also mentioned T. duratii for the country, but it was not until Smith (1972) that the species was associated with a voucher specimen for the first time. The oldest known gathering of T. duratii for Uruguay dates back to 1901 ( Berro 1328, MVFA), collected in Artigas department.

Note I:— Currently, there are two varieties of Tillandsia duratii accepted ( Zuloaga et al. 2019), T. duratii var. duratii and T. duratii var. saxatilis ( Hassler 1919: 329) L.B. Smith (1968: 78) . According to Smith & Downs (1977), the typical variety has 2-pinnate inflorescences, erect spikes, and densely lepidote floral bracts, while T. duratii var. saxatilis has 2 to 3 pinnate inflorescences, curved and divergent spikes, and glabrous or subglabrous floral bracts. In nature, there are individuals clearly belonging to either one of the varieties; however, several materials show intermediate characteristics between them. Based on this evidence, even when all the Uruguayan material examined matches the characteristics of T. duratii var. duratii , here we do not recognize infraspecific taxa for T. duratii . We believe that new morphological and molecular studies are necessary to clarify the infraspecific classification of this species.

Note II: —As stated in the protologue, Tillandsia duratii was described from cultivated material at Padua ( Italy), originally received from Marcello Durazzo in Genova ( Italy). Later, Visiani (1854) described the genus Phytarrhiza and transferred T. duratii coining the combination Phytarrhiza duratii . Over a century later, Smith & Downs (1977) suggested with doubts that the type of T. duratii could be located at PAD [“TYPE. Padua Hortus s n (“ holotype PAD? n v)]”, adding that “In the absence of any specimen the species is adequately typified by the original description and illustration”. Recently a specimen matching the information provided in the protologue of T. duratii (H0061569) and with “ Tillandsia duratii ” and “ Phytarrhiza duratii ” handwritten on its label by Visiani was found at Padua. Based on that and in accordance with ICN Art. 9.12, here we designate H0061569 (PAD) as the lectotype for T. duratii .

Notwithstanding the fact that Smith & Downs (1977) cited an illustration (“pl. 29”) as the type for Tillandsia duratii , we were unsuccessful in finding any illustrations associated with the original species description. In this sense, the digital copy of the original publication ( Visiani 1840a, 1840b), accessible through the Biodiversity Heritage Library website, shows no plate 29. Moreover, the staff of the New York Botanical Garden ( US), and the Accademia Galileliana di Scienze, Lettere et Arti ( Italy) libraries, who had access to printed copies, also confirmed that there was no plate 29 in the original publication of T. duratii by Visiani. The citation of a “pl. 29” by Smith & Downs (1977) remains a mystery.

Note III:— Grisebach (1874) cited in the protologue of Tillandsia circinalis “ Cordoba, ad arborum truncos in collibus promontorii S. de Cordoba ” as the only information of the specimen/s in which he based his description. According to Hunziker (1960), the specimens cited by Grisebach (1874) are based on collections of P.G. Lorentz between November 1870 and October 1872. Three specimens matching this information and the description of the species were located, all of them as the gathering Lorentz 512 (B, CORD, GOET). This is consistent with Smith & Downs (1977), who cited Lorentz 512 as the type for T. circinalis but without specifying a single herbarium, thus performing a first-step lectotypification. According to Planchuelo & Ariza Espinar (2015), Lorentz’s collections from Argentina were kept at Museo Botánico Córdoba (CORD) and another set was sent to University of Goettingen (GOET), where Grisebach studied the Argentinian material. Since Grisebach certainly based his studies, at least in part, on material housed at GOET, we designate GOET000430 as the second-step lectotype for T. circinalis .

Additionally, there is another material identified as a possible syntype by Walter Till in VT (UVMVT031027), corresponding to the gathering Lorentz 443. This specimen aligns with the description in the protologue of T. circinalis , and the information written on its label is very similar to the one present on the label of Lorentz 512 (type material). However, since “ Cordoba ” and/or “S. de Cordoba ” (as stated in the protologue) are missing on Lorentz 443 (VT) label, we consider that there is not enough evidence to securely propose this specimen as type material, at least until further clarifying information is found. Furthermore, W. Till found another possible syntype in 1994 at GOET (GOET000431). Even though this specimen belongs to Tillandsia duratii , is from Córdoba, and was also likely collected by Lorentz, there is no explicit indication of this, nor an exact locality match with that of the protologue. Based on all this, we do not consider GOET000431 as type material.

Note IV:— Phytarrhiza circinalis has been cited in the literature ascribing the authorship to É. Morren ex Baker (1889: 166). However, Morren did publish the combination Phytarrhiza circinalis in 1879, with a direct reference to the original publication of Tillandsia circinalis (although with an error in the page citation). Therefore, the name should be cited as Phytarrhiza circinalis (Griseb.) É. Morren and not as Phytarrhiza circinalis (Griseb.) É. Morren ex Baker. It is further confusing that Smith & Downs (1977) and Tropicos.org (2024) have Phytarrhiza circinalis erroneously listed as nomen nudum when, as stated above, the combination was validly published.

Representative specimens examined:— URUGUAY. Artigas: Santa Rosa , 2 September 1901, Berro 1328 ( MVFA) . Paysandú: Meseta de Artigas , 20 September 1970, Del Puerto et al. s.n. ( MVFA 2375 ) . Salto: Espinillar, October 1958, Klappenbach s.n. ( MVM 2945 ) .

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 12. Illustrations of floral parts. A. Tillandsia bandensis subsp. bandensis. B. T. bandensis subsp. grandipetala. C. T. duratii. D. T. myosura. 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. 369 (MVFA); B based on Rossado et al. 408 (MVFA; floral bract and petal) and Rossado et al. 407 (MVJB; sepals and pistil); C based on Rossado et al. 365 (MVFA); D based on Mai 76 (MVJB) and on a cultivated plant from Arequita Hill (petal and pistil).

FIGURE 19. Tillandsia duratii. A. Habitat; open thorn forest near the Mandiyú River (Artigas, Uruguay). B. Habit (near the Mandiyú River). C. Close up of a clump with inflorescences (near the Mandiyú River). D. Close up of the fertile part of the inflorescence. E. Lateral view of the flower. F. Front view of the flower. G. Infructescence. H. Open capsules releasing seeds. I. Detail of immature capsule. Photos by Andrés Rossado.

FIGURE 20. Distribution map of Tillandsia duratii in Uruguay and neighboring areas.