Portraits of Bromeliaceae from the Mexican Yucatan Peninsula-I: Hechtia schottii Baker ex Hemsley by I. Ramirez, F Chi-May, G. Carnevali, F May-Pat & G. Chuc-Puc in J. Brom. Soc. 50: 20-25. 2000
This is the first of a series of articles on Bromeliaceae of the Mexican Yucatan Peninsula. This geographical area is comprised of three states (Quintana Roo, Yucatan, and Campeche), constituting the Mexican portion of the Yucatan Peninsula. The Yucatan Peninsula is located in the southernmost portion of the country, and it is famous for its Mayan ruins, "henequen" production, and beaches on the Caribbean coast (figure 14).
The vegetation types covering the peninsula are correlated with the precipitation and soil type, with dry areas (sand dunes and low caducifolious forests) to the north and wet and taller forests toward the south. There is a precipitation gradient from southeast (wettest) to northwest (driest). The flora comprises an estimated 2,200-2,300 species of which about 168 taxa (ca. 7.3% of the total flora) are currently considered endemics (Duran et al., 1998). This figure is being revised by an ongoing floristic project (Carnevali et al., in prep.), since it appears that the actual number of endemics might be somewhat higher. The Yucatan flora is apparently related to the flora of northern Mesoamerica more than it is to that of the West Indies, as previously thought (Estrada-Loera, 1991). The epiphytic flora is poor compared to other areas of Mexico and the Neotropics. This is certainly due to the predominance of dry vegetation types, recent origin of the area, its flatness (the highest elevation hardly reaches 210 m), and the almost total absence of rivers and other fresh water bodies. The main epiphytic families are Orchidaceae, Bromeliaceae, Cactaceae, and some fern families, a pattern also found in other essentially flat, dry tropical areas (e.g., Gentry and Dodson, 1987).
The family Bromeliaceae is represented by both terrestrial and epiphytic members, but epiphytes are much more common in the area. Most of the species present have wide distributional ranges in the Neotropics, especially in the Caribbean Arch (Smith & Lundell, 1940; Olmsted & Gomez-Juarez, 1997; Ramirez & Carnevali, 1999). Tillandsia is the most diverse genus in the area with 20 species, including a recently proposed new species, Tillandsia may-patii I. Ramirez & Camevali (Ramirez and Carnevali, 1999) and one more, which has only recently been discovered and is yet to be described.
Hechtia schottii, the species we are portraying here, belongs to a genus of almost 50 species, ranging from southern Texas and northern Mexico to northern Nicaragua. With the exception of five species, the genus is endemic to Mexico. In Mexico, states like Oaxaca, Guerrero, and Mexico are particularly well represented. Rosettes are terrestrial with lateral or terminal inflorescences that can reach up to 3 m high in some species. As an interesting characteristic, the genus Hechtia consists mainly of dioecious members (except probably by H. gayii L. W Lent, 1995, described as monoecious). Most of the species are restricted to just a few populations, and are generally associated to rocky soils (mostly of calcareous origin but some grow on volcanic outcrops), usually in exposed situations
Hechtia schottii was previously reported from the states of Yucatan, Veracruz, and San Luis Potosi (Smith and Downs, 1974), the latter two states being in central Mexico. A detailed study of living and herbarium material, however, has revealed that the species is actually restricted to the Yucatan Peninsula, in the states of Yucatan and Campeche. So far, H. schottii is known from only four populations (figure 14). It inhabits open vegetation associations on calcareous soils, often associated with sinkholes (locally known as "cenotes"), growing along with several terrestrial and climbing herbs of different families, mostly Convolvulaceae, Compositae, Euphorbiaceae, and Agavaceae. It also occurs in low caducifolious forests but populations in this habitat do not perform well since they are light-limited. We suppose that in localities where the Hechtia plants are found inside the forests, their current situation of shading is due to the abandonment of old "henequen fields" (Agave fourcroides Lem.), thus creating an open habitat temporally suitable for invasion by Hechtia. Eventually, the forest tree species re-colonize the old field, leaving the long-lived hechtias under the shade of the secondary, successional forest. Under these conditions, the stems and leaves etiolate and become unduly elongate, and the plants fail to bloom and fruit properly.
Hechtia schottii is a dioecious species, with male and female sexes on separate individuals. Inflorescences are lateral so rosettes are polycarpic. Flowers of both sexes are white, sweetly fragrant; female flowers have white stigmas (figure 16), and male flowers have green anthers and yellow pollen (figure 17). Flowering is mostly during the dry season (December-April) and fruit setting is very high, producing dry dehiscing capsules, with numerous dry seeds that fall close to the parent plant. Flowers are visited by several insects, mostly bees (native and exotic species), wasps, ants, and several other larger insects, that probably also use inflorescences as places to stalk and trap smaller prey.
Studies regarding population structure, sex ratios, floral and reproductive biology are being conducted in three out of the four known populations of the species in the peninsula (I. Ramirez et al., unpublished). These studies are aimed at understanding the reproductive strategy of the species and getting the essential knowledge to meaningfully propose a plan to protect the few populations of the species.
Hechtia schottii is endemic to the Yucatan Peninsula. Male flowers represent a very important source of pollen for the honey-producing insects in the area (Trigona spp., Melipona spp., Nannotrigona spp., and Apis mellifera). Unfortunately, the largest known population of the species is located close to the Calcehtok caverns, near the village of the same name, a famous tourist destination in the northwestern Yucatan state. The attractiveness of the caverns has brought about some undesirable side effects along with the frequent visitors. These include clearing of the natural vegetation (it is perceived as thorny and scrubby, thus, undesirable), littering of the area, and generation of periodic fires during the dry season. These seasonal fires cause the death of many Hechtia individuals and of most of the seeds that are shed prior to the rainy season.
Besides the biological interest of the plant, Hechtia schottii is of easy cultivation if provided with a large container and a well-drained, terrestrial substrate. The plants require exposure to fairly high light intensities if they are to be grown to a healthy, natural-looking appearance. The plants must reach a certain critical size to bloom, and eventually become too large for most greenhouses. The leaves are very spiny and the plants should be kept out of the way and handled carefully. Hechtia schottii is, therefore, along with many other Hechtia species, more amenable as a landscape plant under tropical and subtropical conditions. Nothing is known about its tolerance to frost, but since it comes from a low elevation and tropical conditions, we suppose it will not be able to withstand below-freezing temperatures for any length of time. Furthermore, the polycarpic characteristics of the genus make the plants very appealing since the rosettes are extremely long lasting and do not require the frequent trimming or removal of old, dying rosettes, so typical of most bromeliads. Seeds germinate easily (in the lab) and are viable for long periods if kept in dry, cool conditions. The plants also produce long, creeping stolons, which can be used to reproduce them but that if left besides the mother rosette, will eventually produce a large, showy clump. With such care, plants of Hechtia schottii (and of many other Hechtias) will become very showy healthy specimens which will reward bromeliad lovers with several many-flowered male or female inflorescences a year and showy, large, compact spiny rosettes, much in the way of some Agave species. —SeeSmith & Downs 1974
