Tillandsia bandensis subsp. grandipetala Rossado

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

3b. Tillandsia bandensis subsp. grandipetala Rossado in Rossado et al. (2019: 20). Figs. 12B , 14 , and 15.

Type (holotype):— URUGUAY. Treinta y Tres: Quebrada de los Cuervos , 16–18 December 1964, Brescia & Marchesi s.n. ( MVFA0000944 !) .

Plants mainly epilithic, forming subdense to dense semiglobose clumps. Stems short to long, 50–180 mm long, when long then pendant for most of its length and apically ascending. Peduncles of the inflorescence 0.9–1.2 mm in diameter (live), apical portion subdensely lepidote to subglabrous, occasionally glabrous or densely lepidote; floral bracts densely lepidote to subdensely lepidote, generally trichomes denser towards margins and apex, sometimes the middle portion centrally sparsely lepidote or glabrous; basal floral bracts (10.5–) 11.5–16 mm long. Flowers (15–) 17–22 mm long, strongly fragrant; sepals (10.5–)11–14.5(–15) mm long, with some trichomes arranged in 1 to 3 lines and placed submarginally above the connate portion, occasionally with some trichomes placed also towards the apex, sometimes the sepals of apical flowers totally glabrous; petals 19–27.5 mm long; limbs (7.8–) 8.9–11 mm wide, spreading to slightly reflexed, mainly orbicular. Capsules (17–)19–28 × 1.9–2.6 mm, narrowly ellipsoid-prismatic.

Vernacular names:— Not known.

Distribution and habitat:— Tillandsia bandensis subsp. grandipetala occurs exclusively in eastern Uruguay, in the northeastern region of the Cuchilla Grande hill system (Cerro Largo and Treinta y Tres departments; Fig. 14 ), where it grows as epilithic mainly on vertical rocky surfaces of small gorges, generally together with some cacti species ( Fig. 15B ). This subspecies seldom grows as an epiphyte on branches of trees near the rocky surfaces where it is more abundant. It is important to note that most of the known records of T. bandensis subsp. grandipetala are from the protected area ‘Paisaje Protegido Quebrada de los Cuervos y Sierras del Yerbal’.

Phenology:— Tillandsia bandensis subsp. grandipetala flowers from late spring to early summer, between mid-November and mid-January, with the peak blooming occurring in December ( Fig. 4 ). Fruiting as of January and seed dispersal occurring in winter (from June to early September). The development of the inflorescence takes between two and three months and the complete reproductive cycle lasts from nine to 12 months. It is noteworthy that the phenology of this subspecies is very similar to that of the typical subspecies. Nevertheless, for any given year T. bandensis subsp. grandipetala tends to flower and disperse its seeds earlier than the typical subspecies ( Fig. 4 ).

Conservation assessment:— The estimated EOO and AOO for Tillandsia bandensis subsp. grandipetala were 69 km 2 and 16 km 2, respectively. This subspecies has scattered populations in a restricted area in eastern Uruguay. Fortunately, the rocky habitats where it grows are well-preserved, and most of them are located in the protected area ‘Paisaje Protegido Quebrada de los Cuervos y Sierras del Yerbal’. However, some populations of this subspecies have been observed to be adversely affected by disturbances caused by goats, an invasive species in the region.

Based on the EOO result, the small number of populations registered, and the threat posed to some of these populations by goat disturbances, we tentatively recommend classifying T. bandensis subsp. grandipetala as Critically Endangered (CR) (B1-a and b criteria of the IUCN guidelines).

Background in Uruguay:— This subspecies was published as new in 2019 based on herbarium specimens collected in Uruguay. The oldest gathering of T. bandensis subsp. grandipetala dates from 1964 (Marchesi 1270, MVFA).

Representative specimens examined:— URUGUAY. Cerro Largo: Estancia Perdomo, 10 November 1965, Arrillaga et al. 2390 ( MVFA) . Treinta y Tres: Arroyo Yerbal chico, cerca desembocadura cañada de la Crucera (muy cerca de la Quebrada de los Cuervos), 7 December 2014, Rossado et al. 408 ( MVFA) .

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 14. Distribution map of Tillandsia bandensis subsp. bandensis (red circles) and T. bandensis subsp. grandipetala (green circles) in Uruguay and neighboring areas.

FIGURE 15. Tillandsia bandensis subsp. grandipetala. A. General view of the habitat (plants growing on rocky blocks; protected area ‘Paisaje Protegido Quebrada de los Cuervos y Sierras del Yerbal’, Treinta y Tres, Uruguay). B. Plants in habitat (protected area ‘Paisaje Protegido Quebrada de los Cuervos y Sierras del Yerbal’, Treinta y Tres, Uruguay). C. Habit (Yerbal Chico River, Treinta y Tres, Uruguay). D. Front view of the flower. E. Lateral view of the flower with its floral bract. F. Capsule. Photos by Andrés Rossado.