Werauhia nutans (L.B.Sm.) J.R.Grant
Taxonomic Change:
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- The Presence of Werauhia nutans in Mexico by Thorsten Kromer, Adolfo Espejo, Ana Rosa Lopez-Ferrari & Amparo Acebey. In J. Brom. Soc. 55(6): 280-4. 2005
The genus Werauhia was described by Grant (1995a), for sixty-six taxa previously attributed to Vriesea section Xiphion. Most members of this genus have a nocturnal anthesis, a general lack of brilliant coloration, mostly fleshy frequently secund bracts and flowers, bilaterally symmetric and often zygomorphic corollas, dactyloid petal appendages, stigma with a cupulate-type morphology, and stout, dark colored capsules. Many species of Werauhia are known to be chiropteriphilous, which means pollinated by bats (Grant 1995a, Benzing 2000, Kromer 2004). Their floral syndrome thus includes relatively large, bell-shaped (campanulate) flowers with brown or green bracts, greenish to whitish petals, and often a specific smell.
At this time Werauhia comprises ca. 93 species (see Grant 1995a, 1995b, 1995c, 2000; Luther 1998, 2002a, 2002b, 2002c; Pierce & Aranda 2000; Pierce 2001; Morales 2003a, 2005; Barfuss et al. 2004;The International Plant Names Index 2006). The distribution of Werauhia ranges from southern Mexico throughout Central America, the West Indies, Northeastern Brazil to Bolivia. However, its center of diversity is found in Costa Rica and Western Panama, where about 80 of these species are distributed (Morales 2005). For Mexico, Espejo et al. (2004) have reported six taxa: Werauhia gladioliflora (H. Wendl.) J.R. Grant, W. nocturna (Matuda) J.R. Grant, W. pectinata (L.B. Sm.) J.R. Grant, W. pycnantha (L.B. Sm.) J.R. Grant, W. vanhyningii (L. B. Sm.) J.R. Grant, and W. werckleana (Mez) J.R. Grant.
During a field trip for a current research project, T Kromer and A.Acebey collected two specimens of Werauhia on the slopes of the San Martin Tuxtla volcano, located in the northeastern region of Los Tuxtlas, in the state of Veracruz. This material could not be identified to any of the species of this genus reported from Mexico. After a careful revision of bibliography, bromeliad databases, type specimens, and Mexican and foreign collections, we concluded that these specimens pertain to Werauhia nutans (L.B. Sm.) J.R. Grant. This species was previously known as Vriesea nutans L.B. Sm. only from the type specimen collected in Costa Rica (Smith 1960; Smith & Downs 1977; Utley & Utley 1994; Luther 1995). Additionally, in Mexico there exist two further collections of the species, one from the area of Santa Maria Chimalapa, in the state of Oaxaca (P. Tenorio & T. Wendt 19335, depauperate) and another from the state of Chiapas (E. Martinez S & M.A. Soto A. 18654).
In Mexico, Werauhia nutans co-occurs with other bromeliads such as Catopsis sessiliflora, Tillandsia punctulata, T. viridiflora, and a still unidentified species of Werauhia in the lower montane forest of the San Martin Tuxtla volcano between 650-1400 m elevation. As most of the original forest extent of the region of Los Tuxtlas had been cleared by the year 1990, the lower slopes of the volcano are currently covered by a vegetation mosaic dominated by pastures, with small patches of remnant trees and different types of field crops surrounding the remaining forest fragments. At about 1000-1550 m elevation mostly undisturbed humid montane forest can be found, while the summit of the volcano is covered by dwarf cloud forest. A preliminary checklist of the bromeliads occurring in this area lists 32 species in 9 genera, including five species of Werauhia (Kromer & Acebey, in press), whereas W nutans and W. Spec. (T. Kromer & A. Acebey 2207, 2507) increase the number of species from Mexico reported for this genus to eight. A detailed description of these two species is published in the Bromeliaceae of The Flora of Veracruz (Espejo et al. 2005).
Although Werauhia nutans is so far only known from two records in the Los Tuxtlas region, it is a locally abundant species in some spots along trails below 1000 m elevation. It is epiphytic and due to its strong vegetative reproduction it forms dense colonies mainly on the trunks of trees in the understory level where its inconspicuous, arching inflorescence is projected into the open air. The few (5-11) white flowers open on consecutive days at dawn . This species is likely pollinated by any one of the nine nectar-feeding bats (Phyllostomidae: Glossophaginae and Phyllostominae), that occur in this area (Estrada & Coates-Estrada 2001). Similar to Werauhia gladioliflora, a species co-occuring at 700 m elevation, the flowers of Werauhia nutans fit like a "head-mask" on the elongated rostrum of the nectar-feeding bat, while the exposure of the inflorescence provides space for wing movements of the bat during hovering or feeding bouts (Kromer 2004).
It should be mentioned, that Morales (2003b) in his treatment of Bromeliaceae for the Manual de Plantas de Costa Rica considered Werauhia nutans as a synonym of Werauhia viridiflora, although without giving a broader explication for his decision. Werauhia viridiflora itself is being accepted as quite a variable species with a wide geographical range, which probably represents a complex of several species. However, Utley & Burt-Utley (1994) in their treatment of Vriesea for the Flora Mesoamericana considered both as distinct species. As to our knowledge (J.E Morales, pers. com.) the type of Werauhia viridiflora (Pitcairnia viridiflora Regel) is lost, it was not possible to make a specific revision to solve this unclear nomenclature. Furthermore, all specimens revised within this study without doubt corresponded to the type of Vriesea nutans, which was examined by A. Espejo and A.R. Lopez-Ferrari at the National Herbarium of the United States (US). For these reasons, we prefer to use Werauhia nutans as scientific name for the Mexican specimens.
Werauhia nutans (L.B. Sm.) J.R. Grant, Phytologia 79: 255.1995. - Vriesea nutans L.B. Sm., Phytologia 7: 175. 1960. Type: Costa Rica, San Jose, on tree, road from Turrialba to Moravia, M.B. Foster 2717 (Holotype: US!). —See Smith & Downs 1977
