Abstract:<p>Se realizó una sinopsis taxonómica del género Croton en los Andes de Mérida, Venezuela. Se analizaron caracteres vegetativos en 245 especímenes y se hizo un análisis de agrupamiento que resultó en la identificación de 21 grupos discretos a los cuales les fueron asignadas las identidades taxonómicas específicas más apropiadas. De estas 21 especies, C. pedicellatus representa un nuevo registro para Venezuela, C. fragilis, C. speciosus y C. redolens son nuevos registros para la región andina. Se proponen… Show more
“…However, our results show that the use of anatomical characters could facilitate taxonomic delimitation at the species level in sections of Croton, and it is possible that using anatomical and morphological characters in combination could be even more useful for establishing species limits. There is a recent study establishing species limits in Croton occurring in a region of the northern Andes (Luján, León & Riina, 2015), but these authors only analysed vegetative morphological characters.…”
Section: Delimitation Of Groups and Taxonomic Implicationsmentioning
Establishing species limits in clades in Croton using characters from external morphology and common molecular markers has proved cumbersome, especially in Croton section Cyclostigma, a group of 50 Neotropical arborescent species commonly known as dragon's blood. Given this, we explored leaf and shoot apex anatomical characters for their utility in distinguishing species or groups of species in this section. We analysed 90 specimens belonging to section Cyclostigma and 14 specimens from related groups (sections Adenophylli, Cupreati and Sampatik), recording and describing 45 qualitative leaf characters. These characters were assembled into a matrix and analysed using statistical clustering methods based on similarity. Our results show that trichomes are one of the most diverse and variable anatomical features among the studied specimens. Novel anatomical features for Croton include the presence of a hypodermis and two previously unreported types of non-glandular trichomes. Although we did not detect a single anatomical character uniting section Cyclostigma, combinations of anatomical characters were useful to establish species limits and taxonomic identities within this section.
“…However, our results show that the use of anatomical characters could facilitate taxonomic delimitation at the species level in sections of Croton, and it is possible that using anatomical and morphological characters in combination could be even more useful for establishing species limits. There is a recent study establishing species limits in Croton occurring in a region of the northern Andes (Luján, León & Riina, 2015), but these authors only analysed vegetative morphological characters.…”
Section: Delimitation Of Groups and Taxonomic Implicationsmentioning
Establishing species limits in clades in Croton using characters from external morphology and common molecular markers has proved cumbersome, especially in Croton section Cyclostigma, a group of 50 Neotropical arborescent species commonly known as dragon's blood. Given this, we explored leaf and shoot apex anatomical characters for their utility in distinguishing species or groups of species in this section. We analysed 90 specimens belonging to section Cyclostigma and 14 specimens from related groups (sections Adenophylli, Cupreati and Sampatik), recording and describing 45 qualitative leaf characters. These characters were assembled into a matrix and analysed using statistical clustering methods based on similarity. Our results show that trichomes are one of the most diverse and variable anatomical features among the studied specimens. Novel anatomical features for Croton include the presence of a hypodermis and two previously unreported types of non-glandular trichomes. Although we did not detect a single anatomical character uniting section Cyclostigma, combinations of anatomical characters were useful to establish species limits and taxonomic identities within this section.
“…El género Croton Linnaeus, 1753 es predominantemente arbustivo, aunque también incluye hierbas, árboles y ocasionalmente lianas constituyendo elementos importantes de la vegetación secundaria (Berry et al 2005). En Venezuela, Croton es el género mejor representado de la familia Euphorbiaceae con 79 especies (Luján et al 2015). De acuerdo con nuestras observaciones, C. conduplicatus habita en ambientes periurbanos en un sistema sucesional de bosque estacionalmente seco entre los 1.180 y 1.590 msnm en suelos inclinados de textura franco arenosa.…”
Se reporta por primera vez a Agonosoma trilineatum (Fabricius) alimentándose de Croton conduplicatus Kunth (Euphorbiaceae), además, se confirma la condición dimórfica en los machos en cuanto al patrón de color exhibido en un sistema sucesional de bosque estacionalmente seco en Mérida, Venezuela.
“…Croton is a genus in the Euphorbiaceae family with about 1,300 widely distributed species in tropical and subtropical regions, mainly in arid and semi-arid areas, with greater diversity in Brazil, Madagascar and the Caribbean (Luján et al, 2015). It is the second most numerous and diverse genus and encompasses herbs and trees with varied leaf forms, with glands at the base of the leaf or on the petiolo and female flowers with reduced or absent petals.…”
mentioning
confidence: 99%
“…It is the second most numerous and diverse genus and encompasses herbs and trees with varied leaf forms, with glands at the base of the leaf or on the petiolo and female flowers with reduced or absent petals. Most Croton species have secretory structures such as floral and extrafloral nectaries (Salatino et al, 2007;Luján et al, 2015) and have abundant compounds with biological activity, mainly diterpenoids and active alkaloids (Milanowski et al, 2002;Block et al, 2004). Taspine is a minor alkaloid found in the sap of mature trees (Perdue et al, 1979).…”
Genetic variability studies on species with a pharmacological potential are essential for conserving genetic resources. A genetic characterization of a species can guide efforts to collect and conserve germplasm for future breeding programs. The Croton genus belongs to the Euphorbiaceae family, which has approximately 1,300 species, is widely distributed in tropical and subtropical regions of the world, and has a wide range of ethnobotanical and medicinal uses. The aim of this research was to study genetic variability by analyzing sequences of the internal transcribed space region (ITS1 5'-TCCGTAGGGAACCTGCGGC-3' and ITS4 5'-TCCTCCGCTTATGC-3') of ribosomal DNA (rDNA) of a Croton population from forested areas in the Department of Norte de Santander in the municipalities of Chinacota, Pamplona and El Zulia. The results indicated considerable genetic variability in the Croton population, with a nucleotide similarity ranging from 54 to 99% and phylogenetical grouping according to the place of origin. The information gained from the ITS region can be a useful parameter for diversity evaluations and phylogenetic studies since there are no similar studies on Croton in this department in northeastern Colombia.
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