This description builds on the original one provided by L.B. Smith (1964) and the revised version of McVaugh (1989). Our report includes descriptions of petals, fruits and seed which were previously unknown. McVaugh (1989), indicates in his description that sepals have «...long subulate tips becoming twisted together or coiled in drying, ...» but we were unable to observe this. Rather, in dry material, we have seen that the apices of petals in unopened buds have such features.
-Distribution. Endemic to western Mexico. Known only from the type locality in Nayarit and the Santiago River basin in Jalisco. The new collections reported herein from Nayarit are presumably from the type locality, which apparently hadn’t been revisited since the initial collection in 1959 by McVaugh. Fourteen species of Pitcairnia have been reported in Jalisco and Nayarit (Espejo and López-Ferrari, 1994) of which, 12 have red flowers and only two have greenish-white flowers, namely P. abundans and P. imbricata.
-Habitat. Rupicolous on large rocks near creeks in barrancas, in tropical deciduous forest near the ecotone with oak forest in cool, protected but well lit spots under the canopy. Growing together with Alvaradoa amorphoides Liebm., Bursera bipinnata (Sessé & Moc. ex DC.) Engl., B. fagaroides (Kunth) Engl., Cochlospermum vitifolium Spreng., Euphorbia calcarata (Millsp.) V.W. Steinm., Leucaena esculenta (Moc. & Sessé ex DC.) Benth., Lysiloma microphyllum Benth., Opuntia sp., Pereskiopsis aquosa (F.A.C. Weber) Britton & Rose, Plumeria rubra L., Pouzolzia sp., Trema micrantha (L.) Blume, and bambusoid plants. Elevation. 1100-1350 m.
Extension of the known geographic distribution of Pitcairnia abundans L.B.Sm. The new location in Jalisco hereby reported extends the known distribution range of P. abundans about 115 km from the type locality in Nayarit; however no additional populations were found between the two known disjunct populations. Both sites are in a region known as the Mexican Transversal Volcanic Belt; the Nayarit location is part of the Ameca river basin and the one in Jalisco is located in the Santiago River Canyon. Interestingly, both locations are very similar in vegetation composition, elevation and latitude. We observed that, as far as known, this is a strictly endemic species with very limited distribution. In the Jalisco population, very few individuals were seen in only one site, despite much exploration in the area. Although the Nayarit region was not as thoroughly explored, a similar pattern of localized distribution was also noticed. The observed scarcity of this species prompted an evaluation of its conservation status which may help protect it in the future. Since the known populations of Pitcairnia abundans are very restricted and grow in areas that are difficult to access, future exploration in western Mexico may reveal additional stands.
Conservation status a) Geographic distribution: Scores range from 1-4. After analyzing the known distribution range of this species, we assign it a score of 4 due to the reduced area it occupies. Pitcairnia abundans is found in a short ravine in Nayarit and in two small adjacent clumps in Jalisco. This extension amounts to much less than 5% of the territory of Mexico. b) Habitat condition: Scores range from 1- 3. We gave P. abundans a score of 3 due to the combination of similar environmental factors of the two regions where it grows such as a humid and partly shady environment, rupicolous habit by creeks on the ecotone of oak forest and tropical deciduous forest, similar elevation and latitude. This would suggest a narrow tolerance to environmental change. c) Intrinsic biologic vulnerability: Scores range from 1-3. We assigned this criterion a value of 3 because of its monocarpic shoots which require at least two years to flower, its nocturnal or crepuscular habit with little observable recruitment and the fact that many of the plants are clones, which suggests little genetic variability. Also, there is no information on the dispersal and germination of the seeds but the evidence at hand points to low success rates. It seems that the species has been able to survive due to its ability for vegetative reproduction. d) Impact of human activity: Scores range from 2-4. We gave this criterion a low value of 2 since the species grows in ravines that are difficult to access and therefore have little use for agriculture. Also, the plants have no known local uses. The assigned values for the evaluated criteria total 12, which on the MER scale correspond to a status of endangered species. Pitcairnia abundans would be the first species in this genus to be afforded legal protection by NOM-059-SEMARNAT- 2001. Although several other species in this genus may result endangered or threatened using MER methodology this does not necessarily mean that the method is excessively permissive in affording protected status to a plant species. In fact, the method uses a wide range of characteristics to evaluate a species’ status in an effort to offset the effect of using just a single factor, such as a very limited geographic distribution. This ensures that species afforded legal protection would do so as a result of a realistic and objective analysis. So far the method has proven effective, as the list of species under protection has not grown out of control (the plant list is available at http://www. conabio.gob.mx/conocimiento/ise/fichas/ doctos/plantas.html). —SeeMacias ea. 2007
