Tillandsia tragophoba M.O.Dillon
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Authority
Dillon, M. O. 1991. A New Species of Tillandsia (Bromeliaceae) from the Atacama Desert of Northern Chile. Brittonia. 43 (1): 11-16.
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Family
Bromeliaceae
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Scientific Name
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Discussion
Habitu cum Tillandsia sceptriformi Mez & Sodiro optime congruens, sed foliis 40-65 cm longis, 5-7 cm latis, spicis ca 7-floris, 4-6 cm longis, ca 2 cm latis differt.
TYPE: CHILE. ANTOFAGASTA (Regi6n II), Prov. Antofagasta, Quebrada Rin- conada, ca. 5 km N of Caleta Paposo, (24º56'S, 70º30'W), 240-440 m alt., 4 Nov 1988, M. 0. Dillon & D. Dillon 5869 (HOLOTYPE: SGO; ISOTYPES: F, SEL, SSUC, US).
Etymology: The specific epithet is derived from the Greek "tragos" (goat) and "phobos" (fear) and is in reference to this species occupying steep rock faces virtually inaccessible to the large local goat population at the type locality.
Ecology: Tillandsia tragophoba occupies rocky outcrops, usually on west- and northwest-facing steep slopes, between 350 and 450 m elevation and in view of the ocean (Figs. 2, 3). The flora of the region is part of the lomas formation of the northern Atacama Desert, a highly endemic, fog-dependent community found along the arid coastal escarpment (Johnston, 1929). The physical and ecological parameters of these communities have recently been discussed in detail (Rundel et al., 1991), but it should be noted that this locality is extremely arid and receives, on average, less than 25 mm ppt/yr. The primary source of moisture is the seasonal fog, termed camanchaca, which bathes the coastal escarpment be- tween 200 and 800 m and allows the development of perennial vegetation. It is likely, therefore, that fog is condensed on the leaves and collects in the basal tanks. When this population was discovered in November 1988, all individuals examined contained between 250 and 500 cc of liquid; however, there had been no recorded rainfall in the region since July 1987.
Other members of the community rely upon moisture derived from condensation on plant substrates and vegetation. It is notable that T. geissei Philippi grows in complete sympatry with T. tragophoba. Other associates include a number of local endemics, such as, Calceolaria paposana Philippi (Scrophulariaceae), Seneciopaposanus Philippi (Asteraceae), Proustia tipia Philippi (Asteraceae), Croton chilensis Muell.-Arg. (Euphorbiaceae), and Griselinia sp. nov. (Cornaceae).
The probable relationships of this new species suggest an interesting biogeo- graphic disjunction. The 13 species of Tillandsia from western South America are distributed in four subgenera (Table I), suggesting that the genus has moved into these arid environments from several independent lineages. The nearest geographic neighbors to T. tragophoba are T. geissei and T. landbeckii, both primarily Chilean species. Tillandsia geissei is overall quite similar to T. latifolia Meyen of subgenus Allardtia (A. Dietrich) Baker, but has been placed in subgenus Anoplophytum (Beer) Baker (Smith, 1977). Tillandsia landbeckii is similar to T. capillaris Ruiz & Pavon and placed in subgenus Diaphoranthema (Beer) Baker (Smith, 1977). These species have small, densely lepidote, gray leaves and simple inflorescences quite unlike T. tragophoba. The only other lomas-inhabiting species with leaf morphology capable of capturing and holding water is T. multiflora Benth. from Cerro Campana (7º58'S, 79º06'W) in northern Peru. Smith (1977) placed this species in subgenus Pseudocatopsis Baker, and it varies greatly from T. tragophoba in having tripinnate inflorescences, 15- to 20-flowered spikes, and short, asymmetric sepals.
Utilizing Smith's (1977) classification system, T. tragophoba is best placed in subgenus Allardtia. This group contains about 150 species possessing symmetric sepals, distinct petals, included stamens equalling or shorter than the petals, straight filaments, and slender styles much longer than the ovary (Smith, 1977). Several Tillandsias found within the lomas community are placed in subgenus Allardtia (Table I); none, however, display morphological similarity to T. tragophoba. Rath- er, T. tragophoba most closely resembles a group of species distributed in upland savannas, montane forests, and subp'aramos (2000-3500 m) from Colombia to Peru, including T. orbicularis L. B. Smith, T. pastensis Andre, T. pachyaxon L. B. Smith, T. sceptriformis Mez & Sodiro, and T. sodiroi Mez
Using the artificial key provided by Smith (1977, p. 671) T. tragophoba would roughly lead to Subkey XI (p. 693) and further to T. sceptriformis. This Ecuadorian species differs in possessing shorter, but wider and more ligulate, usually red leaves, longer and more robust scapes, and larger spikes (Fig. 5). The similarities in overall morphology between T. tragophoba and various equatorial Andean Tillandsias suggests that the origins of this new species are north in the Andean province. While this type of disjunction is not common within the lomas formations northern Chile, small seed size and plumose appendages would allow for ease of transport by some agent, most probably birds (Carlquist, 1983). Further study will be necessary to more clearly define the relationships of this new species.
Lastly, a few words about the future of this plant and its associates: I have applied this rather homely moniker to this handsome plant in an effort to call attention to the rapid and continuing destruction of natural vegetation by grazing animals throughout the lomas formations of Peru and northern Chile. The conditions around Quebrada Rinconada are reaching a critical point due to the vast numbers of domesticated and feral goats consuming the natural vegetation. Some plants are only found on inaccessible rock outcrops. Others, such as the leaf succulent, Anisomeria littoralis (P. & E.) Moq. (Phytolaccaceae), appear to be persisting only within the protection of larger spiny shrubs and arborescent cacti. Within recent years, the seriousness of the situation has been recognized by botanists and personnel in the Corporacion Nacional Forestal, the principal governmental conservation agency in Chile. Active efforts are now being made to insure the continued existence of this unique and highly threatened community through a reduction in the number of grazing animals overall and a viable management program