Deuterocohnia chrysantha by Georg Zizka in J Brom Soc 53(4): 147-150. 2003
The Chilean flora comprises approximately 5660 species of higher plants, of which 2727 are endemic ( 48.1 %) (Marticorena 1991). Bromeliaceae, with 23 species of the genera Puya (7 species), Tillandsia (6), Ochagavia ( 4), Greigia ( 4), Fascicularia (1) and Deuterocohnia (1), display a comparatively low diversity in Chile. Nevertheless most of these species are endemic to the country with the only exception of Tillandsia usneoides, T. virescens, T. marconae, and T. landbeckii. With the exception of the widely distributed T. usneoides, the other tillandsias extend to the arid regions of adjacent Peru; T. virescens is also found in Bolivia and Argentina. In Chile, these species are restricted to the northern part of the country and display interesting disjunct distributions.
In addition to the high endemism levels, Chilean bromeliads are of interest as to the biogeography and evolution of the bromeliad family, especially in relation to its southern border. Fascicularia and Ochagavia are endemic genera, whose systematic relationships among the Bromelioideae remain unclear. The genus Greigia, being of principally Andean distribution, is represented with four species in the humid-temperate Valdivian lowland forests of Southern Chile and on Robinson Crusoe Island. The Chilean puyas represent both known subgenera and occur, as does Deuterocohnia chrysantha, well separated from the area of the other species of their genus. The Chilean bromeliads have recently been revised for the "Flora de Chile" (Zizka & Nelson 1997, Will & Zizka 1999, Zizka et al.1999, 2002).
Deuterocohnia chrysantha resembles "typical" terrestrial pitcairnioid bromeliads from arid regions with succulent leaves in a dense rosette, often of a reddish-brown color. The axes form a considerable number of lateral branches, but unlike, for example some hechtias, the lateral axes are not long caulescent but comparatively short, thus resulting in a dense, hemispherical, cushion-like growth habit (FIGURE 1). These "cushions" reach a height up to about 50 cm and a diameter to over 1 m. The leaves have a straw-colored sheath 1.5-2.5 x 3.1-5.5 cm, glabrous and suborbicular and distinct from the blade. The blade is 10-25.5 x 2.2-4.3 cm, spinose-serrate with retrorsely curved spines 0.5-0.7 cm long, triangular, reddish-brown, densely lepidote below and densely lepidote to ca. glabrous above. As in other Deuterocohnia species (except those formerly placed in Abromeitiella), D. chrysantha produces persistent, woody inflorescences to 1.5 m high (FIGURE 2). Each vegetation period, new lateral, simple flowering branches 4-18 cm long are produced from dormant buds of the woody inflorescence axes, bearing numerous sessile, conspicuous yellow flowers 2.0-2.5 cm long in the axil of a brownish, ca. coriaceous, glabrous, acuminate bract. The 3 brownish, oblong to obovate sepals are 0.8-1.0 x 0.4-0.5 cm, have a rounded, emarginate apex, and are coriaceous with membranous margins. The 3 yellow, apically ca. greenish, spathulate petals are 1.7-2.3 x 0.7-0.8 cm, membranous, the apex ca. emarginate, sometimes with a short mucro; adaxially they bear one scale with 3 irregular, acute apical lobes. Stamens and style are exserted at flower, the latter exceeding the stamens for about 2-3 mm. The stigma is divided into 3 distinct lobes. The numerous conical seeds are 0.2 x 0.1 cm large, including a lateral, asymmetric appendage.
The inflorescence branches are placed well above the cushionlike vegetative parts, making Deuteracahnia chrysantha an amazing plant in its desert habitats, where it can be found accompanied by species of the cactus genus Copiapoa and other desert plants (FIGURE 3). No pollinators have been observed by the author, but this bromeliad is most probably pollinated by hummingbirds, which where observed to pollinate Puya boliviensis in this area.According to Munoz (1966), who provides a nice illustration of the plant, the Chilean name is Chaguar del jote.
Deuterocohnia chrysantha was first described in 1860 by the famous Chilean botanist R.A. Philippi in his "Flora Atacamensis" as Pitcairnia chrysantha and transferred to the genus Deuterocohnia by Mez in 1894 (nomen) and 1896. It has a comparatively narrow distribution extending from 25°01'-26° 41 'S and 70° 24'-70° 45' W (FIGURE 4), occurring from 15-800 m elevation on the western slopes of the Cordillera de la Costa in northern Chile. Mean annual rainfall in these coastal desert regions is very low and highly unpredictable.
Fifteen species are presently recognized by Luther (2000) in the genus Deuterocohnia (incl. Abromeitiella) . The six species of the genus studied by Horres & Zizka (1995; D. brevifolia,D.glandulosa,D.lorentziana,D.lotteae, D. meziana, D. scapigera) display a remarkable degree of leaf succulence, the values of the succulence quotient (after Willert et al. 1990) being comparable to Agave filifera, A. attenuata, or Aloe ramosissima. Deuterocohnia chrysantha is also found growing in highly arid areas of northern Chile. Molecular studies in this genus emphasize the isolated position of D. chrysantha (Horres et al. in prep.).
While some Chilean bromeliads are considered endangered (e.g., Greigia bertereoi from Juan Fernandez Islands and possibly G. pearcei from the mainland), this fortunately appears not to be the case for Deuterocohnia chrysantha, which is relatively abundant throughout its range. —SeeSmith & Downs 1974
