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A specimen of Agave aurea ssp . aurea south of La Paz, Baja California Sur with an unusually tall inflorescence (about 7 m). This inflorescence resembles the one in the photograph of flowering agaves in Balboa Park, San Diego, California that Gentry (1978) used to illustrate Agave prom- ontorii.
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In 1978, Howard Scott Gentry published his second monograph on the genus Agave focusing on the plants of the peninsula of Baja California, México, and the related species in the group Deserticolae in the US and Sonora. We revisit Gentry's work with an emphasis on revising the genus and its taxonomic arrangement and including several recently descri...
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... aurea ssp. aurea shows forms similar to both A. aurea ssp. promontorii and A. aurea var. capensis in the color and form of their leaves. Gentry (1978) dis- cussed this site and suggested that A. aurea ssp. aurea was a recent arrival from the north in geo- logic time. An unusually large form of Agave aurea ssp. aurea that we found south of La Paz (Fig. 4) appears to bridge the gap with A. aurea ssp. promon- torii. In contrast to Gentry's (1978) explanations, we believe these two sites, and the similarity between A. aurea ssp. aurea and A. aurea ssp. promontorii, war- rant reduction of the latter to subspecies status. This reduction is further warranted by A. aurea ssp. aurea populations ...
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... its type locality near Comondú, and A. aurea var. capensis is much small- er and prolifically offsets. Gentry (1978) discussed the A. aurea population north of Todos Santos and remarked on the similarity of plants to A. aurea ssp. promontorii, but observed no individuals of the lat- ter at this locality. A population of A. aurea south of La Paz (Fig. 4) has average sized plants with abnor- mally large flower stalks and an unusual inflorescence structure that resemble those pictured on page 83 in Gentry (1978) and indicates that A. aurea ssp. prom- ontorii warrants subspecies status, and not species ...
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... clearly anchor them within the concept of A. viz- cainoensis. For example, Reid Moran collected speci- mens from Cerro Prieto (Moran 5263-25269, SD), southwest of the Picachos de Santa Clara (Fig. 37), and identified them as A. sebastiana. We visited this population and found plants with closed rosettes and marginal spines on large teats (Fig. 40). As discussed in Webb and Starr (2014b), other specimens identi- fied as A. sebastiana were collected in the vicinity of Bahía Tortugas north to Punta Eugenia; our field in- vestigations in this area yielded highly variable, ma- ny-leaf forms of A. vizcainoensis and no A. sebastiana. Turner et al. (1995) identified A. vizcainoensis in ...
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... the Umbelliflorae can be found above regarding section Intermediae. Members of the Umbelliflorae are mostly in the winter-rainfall regime of the western coast of Baja California. The arid climate of this region is strongly influenced by fog, which provides condensate for additional moisture and reduces air temperature, particularly in the summer. (Fig. ...
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... on the small archipelago off the northwest coast of the Vizcaíno Peninsula and unambiguous individuals have not been found on the mainland despite several herbarium specimens bearing the name of A. sebastiana collected from near Bahía de los Tortugas (Fig. 37) and elsewhere (Webb & Starr 2014b). No other agaves are known from these islands. (Fig. ...
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... shawii ssp. shawii has a restricted distri- bution along the northwest Pacific coast of Baja California (Fig. 44), extending just into the United States, where it is severely threatened by develop- ment (Vanderplank 2014). This coastal habitat, with its fog and cooler air temperatures, contrasts strong- ly with the more arid and interior habitat of Agave shawii ssp. goldmaniana. These two subspecies dif- fer primarily in size and shape of the ...
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... island climate, however the long period of separation of these islands from the peninsula warrant maintaining species status for A. sebastiana. The shorter inflorescences of both A. sebastiana and A. shawii ssp. shawii may be an adap- tation to on-shore winds, which are more persistent than in the areas where A. shawii ssp. goldmaniana occurs. (Fig. ...
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... shawii ssp. goldmaniana occurs in the north-central part of the peninsula, in the southern part of the state of Baja California and generally west of the peninsular divide (Fig. 44). Although Gen- try (1978) discussed gaps in the distribution, he re- marked that this subspecies has a nearly continuous and very large distribution independent of geology and soils. A clear gap occurs between a subpopula- tion that occurs just east of El Rosario and the main population centered on Punta Prieta (Fig. 44). A. ce- rulata ...
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... of the peninsular divide (Fig. 44). Although Gen- try (1978) discussed gaps in the distribution, he re- marked that this subspecies has a nearly continuous and very large distribution independent of geology and soils. A clear gap occurs between a subpopula- tion that occurs just east of El Rosario and the main population centered on Punta Prieta (Fig. 44). A. ce- rulata var. nelsonii is the most common taxa in this gap and is easily distinguished by its smaller rosette, thinner flower stalk, and more open inflorescence. Agave shawii ssp. goldmaniana occurs on both igne- ous and sedimentary rocks, and the densest stands occur in deep granitic alluvium between the Sierra la Asamblea to ...
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... columnaris and Pachycereus pringlei. (1978) found considerable variability in the leaves of Agave shawii ssp. goldmaniana and de- scribed five forms of them, indicating a wide range of vegetative variation in this subspecies. At the southern limit of its distribution, Agave shawii ssp. goldmaniana overlaps with A. avellanidens (Gentry 1978, Fig. 47), and they are so similar vegetatively that the best way to identify them is by the shape of the living or dried inflorescence. A. avellanidens has a tall conical inflorescence with small, nearly incon- spicuous bracts, whereas A. shawii ssp. goldmaniana has a rather broad, shorter and pyramidal inflores- cence with larger, more ...
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... bracts, whereas A. shawii ssp. goldmaniana has a rather broad, shorter and pyramidal inflores- cence with larger, more prominent triangular bracts. A. avellanidens is mostly solitary, whereas A. shawii ssp. goldmaniana is either solitary or offsetting. The two are difficult to distinguish in the coastal hills be- tween Punta Prieta and Rosarito (Figs. 9, ...
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... branches crowded together, thick stalks and enlarged bracts beneath the fertile section and A. avellanidens with the tall and narrow, more cone-like inflorescences, widely spaced side branches, thinner stalks and smaller, more pa- pery bracts below the fertile section. The two are es- pecially difficult to separate in the hills around Ro- sarito (Fig. 47), especially when the inflorescences of Agave shawii ssp. goldmaniana become taller with the side branches more widely spaced and resembling those of A. avellanidens. Further work would be re- quired to determine whether Gentry's (1978) inter- grading of the two species, including his assertion that A. shawii ssp. goldmaniana extends to ...
Similar publications
Polianthes geminiflora (Lex) Rose (Agavaceae) is neotypified and its detailed description is presented. This species was described by Juan Jose Martinez de Lexarza as Bravoa geminiflora and published in Novorum vegetabilium descriptiones in 1824. According to Lexarza, the plant was collected in the mountains of Valladolid, nowadays Morelia, Michoac...
Citations
... Recently (~7 Mya and ~2.5 Mya), agaves experienced two bursts of evolutionary diversification that resulted in many endemic and microendemic species, with countless forms of leaves, rosettes, and inflorescences (Eguiarte et al., 2021;Gentry, 1978Gentry, , 1982Good-Avila et al., 2006;Jiménez-Barrón et al., 2020). On the Baja California Peninsula (BCP hereafter), for example, a total of 23 Agave taxa are found, with 22 of them being endemic (Trelease, 1911;Webb & Starr, 2015). Surprisingly, the rich diversity of agaves in the BCP has been little studied (Gentry, 1978;Webb & Starr, 2015). ...
... On the Baja California Peninsula (BCP hereafter), for example, a total of 23 Agave taxa are found, with 22 of them being endemic (Trelease, 1911;Webb & Starr, 2015). Surprisingly, the rich diversity of agaves in the BCP has been little studied (Gentry, 1978;Webb & Starr, 2015). For example, almost all Agave taxa in BCP represent species/subspecies complexes with unclear geographical boundaries or genetic relationships between and within them (Navarro-Quezada et al., 2003;Webb & Starr, 2015). ...
... Surprisingly, the rich diversity of agaves in the BCP has been little studied (Gentry, 1978;Webb & Starr, 2015). For example, almost all Agave taxa in BCP represent species/subspecies complexes with unclear geographical boundaries or genetic relationships between and within them (Navarro-Quezada et al., 2003;Webb & Starr, 2015). ...
Agaves are an outstanding arid‐adapted group of species that provide a unique chance to study the influence of multiple potential factors (i.e., geological and ecological) on plant population structure and diversification in the heterogeneous environment of the Baja California Peninsula. However, relatively little is known about the phylogeography of the endemic agave species of this region. Herein, we used over 10,000 single‐nucleotide polymorphisms (SNPs) and spatial data from the Agave aurea species complex (i.e., A. aurea ssp. aurea, A. aurea ssp. promontorii, and A. aurea var. capensis) to resolve genetic relationships within this complex and uncover fine‐scale population structure, diversity patterns, and their potential underlying drivers. Analyses resolved low genetic structure within this complex, suggesting that A. aurea is more likely to represent several closely related populations than separate species or varieties/subspecies. We found that geographical and historical ecological characteristics—including precipitation, latitude, and past climatic fluctuations—have played an important role in the spatial distribution of diversity and structure in A. aurea. Finally, species distribution modeling results suggested that climate change will become critical in the extinction risk of A. aurea, with the northernmost population being particularly vulnerable. The low population genetic structure found in A. aurea is consistent with agave's life history, and it is probably related to continuity of distribution, relatively low habitat fragmentation, and dispersion by pollinators. Together, these findings have important implications for management and conservation programs in agave, such as creating and evaluating protected areas and translocating and augmentation of particular populations.
... In the Desert Region, latitude, orientation, and access to groundwater impose varying constraints on plant growth. Such constraints include the latitudinal change in the proportion of winter and summer rains; the influence of coastal fog (Webb and Starr 2015); and the occurrence of shallow aquifers, gullies and dry arroyos embedded within a dryland matrix (Leó n de la Luz and others 2015). Such high contrasts in ecosystem functions between the regional landscape matrix and its embedded ecosystems (that is, less water-limited EFTs within a matrix of dryland EFTs) enhance ecological processes of the lateral transfer of matter and energy (Turner and Gardner 2015). ...
Conservation biology must set geographic conservation priorities not only based on the compositional or structural but also on the functional dimensions of biodiversity. However, assessing functional diversity is challenging at the regional scale. We propose the use of satellite-derived Ecosystem Functional Types (EFTs), defined here as patches of land surface that share similar primary production dynamics, to incorporate such aspects of ecosystem functional diversity into the selection of protected areas. We applied the EFT approach to the Baja California Peninsula, Mexico, to characterize the regional heterogeneity of primary production dynamics in terms of EFTs; to set conservation priorities based on EFT richness and rarity; and to explore whether such EFT-based conservation priorities were consistent with and/or complementary to previous assessments focused on biodiversity composition and structure. EFTs were identified based on three ecosystem functional attributes derived from seasonal dynamics of the Enhanced Vegetation Index: the annual mean (proxy of primary production), the seasonal coefficient of variation (descriptor of seasonality), and the date of maximum (indicator of phenology). EFT-based priorities identified 26% of the peninsula as being of extreme or high priority and reinforced the value of the ecosystem functional diversity of areas already prioritized by traditional conservation assessments. In addition, our study revealed that biodiversity composition- and structure-based assessments had not identified the full range of important areas for EFT diversity and tended to better capture areas of high EFT rarity than those of high EFT richness. Our EFT-based assessment demonstrates how remotely sensed regional heterogeneity in ecosystem functions could reinforce and complement traditional conservation priority setting.
... pecten-aboriginum, Cactaceae) that blooms November-February. Agave species occurred in all ecoregions where bat roosts were located but at lower densities and with less predictable flowering phenologies (Rebman and Roberts 2012; Webb and Starr 2015). ...
... The presence of winter-blooming agaves in the southern peninsula has been suggested as a food resource for lesser longnosed bats that overwinter in the Cape region of Baja (Fleming et al. 1993). While there are 22 species of agave that occur on the Baja peninsula, only 3 species are found in the southern peninsular Cape region (Webb and Starr 2015). Two of these species typically bloom in the spring months from roughly February to April and the other has a typical autumn bloom period from September to December (Rebman and Roberts 2012). ...
Migratory species that cross geopolitical boundaries pose challenges for conservation planning because threats may vary across a species' range and multi-country collaboration is required to implement conservation action plans. The lesser long-nosed bat (Leptonycteris yerbabuenae) is a migratory pollinator bat that was removed from the Endangered Species List in the United States in 2018 and from threatened status in Mexico in 2013. The seasonal ecology and conservation status of the species is well understood in the core part of its range on mainland Mexico and in the southwestern United States, but relatively little is known about the species on the Baja California peninsula in northwestern Mexico, a part of its range range separated by the Gulf of California. We studied the seasonal ecology of lesser long-nosed bats on the Baja peninsula at 8 focal roosts along a 450-km north-to-south transect to test hypotheses about migratory or residential status of the species on the Baja peninsula. We provide evidence of an extensive population of lesser long-nosed bats on the Baja peninsula that is primarily seasonally migratory and includes 2 mating roosts with males on the southern part of the peninsula. Seasonal ecology of lesser long-nosed bats was closely associated with the flowering and fruiting season of the cardón (Pachycereus pringlei), the dominant columnar cactus on the peninsula. However, we discovered that some female lesser long-nosed bats arrive and give birth at southern roosts in mid-February, about 2 months earlier than other migratory populations in more northern Sonoran Desert habitats. We documented the loss of nearly a third of the known maternity roosts during the study, demonstrating that action to protect key roosts remains a high priority. Migratory pollinators are particularly vulnerable to climate and land-use changes and we recommend continued monitoring and research to guide effective range-wide conservation of the species. Las especies migratorias o con rangos de distribución amplios que incluyen fronteras geopolíticas, representan desafíos particulares para la planificación de estrategias de conservación, ya que las amenazas así como las tendencias poblacionales pueden variar a lo largo de su rango geográfico y se requiere la colaboración de múltiples países para implementar planes de acción que permitan su conservación. El murciélago magueyero menor (Leptonycteris yerbabuenae) es un murciélago polinizador migratorio que recientemente fue sacado de la lista de especies en peligro en los Estados Unidos en 2018 y en México en 2013. La ecología estacional y el estatus de conservación de esta especie, ha sido bien estudiado en el centro de su rango de distribución en México continental, pero se sabe muy poco acerca de la especie en la Península de Baja California en el noreste de México, región que está separada del resto del rango por el golfo de California. Nosotros estudiamos la ecología estacional del murciélago magueyero menor, en ocho cuevas a lo largo de un transecto de 450 km norte-sur, en la Península de Baja California y pusimos a prueba la hipótesis del status migratorio o residente de sus poblaciones en esta región. Proporcionamos la primera evidencia de una extensa población de esta especie en la península, a cual es principalmente migratoria estacional e incluye dos cuevas de reproducción ubicadas al sur de esta región. La ecología estacional del murciélago magueyero menor estuvo fuertemente asociada con la estación de floración y fructificación del cardón (Pachycereus pringlei), el cactus columnar dominante en la península. Nosotros también descubrimos que algunas hembras llegan y dan a luz en las cuevas más sureñas, a mediados de febrero, cerca de dos meses antes que otras poblaciones migratorias, en el desierto de Sonora del norte. Durante el tiempo de este estudio, documentamos la destrucción de una de las cuevas de maternidad, lo que demuestra la necesidad de acciones de conservación para proteger estos refugios. Los polinizadores migratorios son particularmente vulnerables a cambios en el uso del suelo y al cambio climático y recomendamos continuar con el monitoreo y la investigación, con el fin de guiar su conservación a lo largo de todo el rango de distribución de la especie.
... I n our recent revision of the Baja Californian species of Agave L., Webb & Starr (2015) transferred to sectional rank four of the informal species groups in Agave Subg. Agave applied by Gentry (1982) and published earlier by Baker (1877) and Trelease (1912) as unranked infrageneric groups. ...
Plant macrofossils from packrat (Neotoma spp.) middens provide direct evidence of past vegetation changes in arid regions of North America. Here we describe the newest version (version 5.0) of the U.S. Geological Survey (USGS) North American Packrat Midden Database. The database contains published and contributed data from 3,331 midden samples collected in southwest Canada, the western United States, and northern Mexico, with samples ranging in age from 48 ka to the present. The database includes original midden-sample macrofossil counts and relative-abundance data along with a standardized relative-abundance scheme that makes it easier to compare macrofossil data across midden-sample sites. In addition to the midden-sample data, this version of the midden database includes calibrated radiocarbon (¹⁴C) ages for the midden samples and plant functional type (PFT) assignments for the midden taxa. We also provide World Wildlife Fund ecoregion assignments and climate and bioclimate data for each midden-sample site location. The data are provided in tabular (.xlsx), comma-separated values (.csv), and relational database (.mdb) files.
A diagnostic description of the genus is given with special emphasis on the occurrence of succulence amongst its species. The geographical distribution is outlined, together with a selection of important literature, and an explanation of the etymology of the name. This is followed by a short summary of its position in the phylogeny of the family and of the past and present classification in a phylogenetic context. The succulent features present amongst the species of the genus are shortly explained as to morphology and anatomy.
This is followed by a synoptical treatment of the species (all succulent) of the genus, complete with typification details, full synonymy, geographical and ecological data, a diagnostic description, and, where applicable, notes on phylogenetic placement and relationships, as well as economic and/or horticultural importance.
A diagnostic description of the genus is given with special emphasis on the occurrence of succulence amongst its species. The geographical distribution is outlined, together with a selection of important literature, and an explanation of the etymology of the name. This is followed by a short summary of its position in the phylogeny of the family and of the past and present classification in a phylogenetic context. The succulent features present amongst the species of the genus are shortly explained as to morphology and anatomy.
This is followed by a synoptical treatment of the species (all succulent) of the genus, complete with typification details, full synonymy, geographical and ecological data, a diagnostic description, and, where applicable, notes on phylogenetic placement and relationships, as well as economic and/or horticultural importance.
An updated infrageneric classification is provided for the genus Agave L. s.l., therefore including A. subg. Manfreda, i.e., the genera Manfreda Salisb., Polianthes L., and Prochnyanthes S.Watson (Asparagaceae: Agavoideae / Agavaceae), with emphasis on the rank of section. Nomenclatural assessments are provided for (1) all unranked infrageneric ‘group’ names introduced by Trelease (1913) for the Caribbean region, by (2) Gentry (1982) for continental North America, and (3) for all infrageneric taxa at sectional rank hitherto published in Agave by Salm-Dyck, Engelmann, Berger, Ullrich, Webb & Starr, Starr & Webb, and Hochstätter. We also show that Jacobi did not publish names at the rank of section. In addition, a revised infrageneric classification of Agave s.l. is provided, including new combinations and new names mainly at the rank of section, especially for those unranked group names used by Trelease (1913) and Gentry (1982) for which no corresponding formal name at sectional rank is available. Three new combinations are made in Agave for species recently described in Manfreda and Polianthes.
