Altitudinal variation of resin ducts in Pinus taiwanensis Hayata (Pinaceae) needles
The variation of resin ducts in needles of Pinus taiwanensis along an altitude gradient (700 m- 3,100 m) in central Taiwan is revealed for the first time in this study, including position type, number, size, arrangement pattern and anatomical structural variation. Three types of resin ducts-medial, external and septal-were found according to their relative positions in the mesophyll. All needles sampled showed combinations of these three resin duct types. Mostly, 3-7 resin ducts were found in the mesophyll per needle, and the number of resin ducts was significantly greater at mid altitudes than at high and low altitudes. Septal ducts decreased in number with an increase in altitude; however, needles from mid altitudes had more external ducts. Eight patterns (basic and patterns I-VII) of resin ducts in the mesophyll of needles were delineated to present the arrangement variations. In addition to the primary ducts found in the mesophyll, we found the rare bundle sheath ducts in some needles, and their frequencies decreased obviously with an increase in altitude. The consistent combination feature of medial, external, and septal ducts in needles of P. taiwanensis from Taiwan could be easily distinguished from those with medial ducts from mainland China. However, this difference has unrecognized before, and it should be considered in future taxonomic work.
Leaf and stem anatomy and essential oil composition of four Brazilian Aldama species (Asteraceae) and their taxonomic significance
Aldama La Llave is one of several Asteraceae genera that pose phylogenetic problems. The close similarity between species, as well as the inconsistencies found in the most recent phylogenetic analysis, shows that new data are needed to help delimit group species. Aldama anchusifolia (DC) E.E.Schill. & Panero, Aldama megapotamica (Malme) Magenta & Pirani, Aldama nudibasilaris (S.F.Blake) E.E.Schill. & Panero and Aldama pilosa (Baker) E.E.Schill. & Panero are difficult to identify because they are very closely related. Therefore, the aim of this study was to detect anatomical and phytochemical characteristics to help elucidate phylogenetic issues raised by Aldama. Aerial vegetative organs were prepared using the standard histological techniques. Essential oils were obtained by hydrodistillation, and their components identified using a gas chromatograph coupled to a mass spectrometer and flame ionization detector. Each species presented a set of unique leaf and stem anatomical features. The front view of the epidermal cell walls in the leaves, the presence of secretory ducts in the phloem and medulla sclerification in the stems proved useful in delimiting these species. The essential oils were characterized by the predominance of sesquiterpenes such as t-caryophyllene, germacrene D and bicyclogermacrene. Some unique constituents in each species were also identified as potential chemical markers.
Indian Fig Cactus (Opuntia Ficus-Indica (L.) Miller) in the Americas: an Uncertain History
Abstract: 
 Opuntia ficus-indica (L.) Miller is a globally important cactus species with a long history of human use. In addition to the importance of O. ficus-indica as a food for humans and livestock, it also has long served a role in the production of cochineal, a once important textile dye. This cactus also is intimately interwoven into the story of Cactoblastis cactorum (Berg) (South American cactus moth), one of the best-known examples of biological weed control. In this regard, O. ficus-indica has been a target weed as well as an unintended host in C. cactorum invasion. Although the distribution and human-assisted movement of this cactus throughout much of the world is well documented, surprisingly little has been written about its history and movement within the Americas. Literature associated with Opuntia and their phytophagous pests in North and South America was examined in an attempt to determine the history of O. ficus-indica in the Americas. Available information suggests with some certainty that O. ficus-indica originated in present-day Mexico, but the timing of its introduction to South America is much less clear. Taxonomic difficulties associated with distinguishing among Opuntia species and the long pre-Columbian history of exchange between South American and Mesoamerican cultures are two primary complicating factors associated with dating the dispersal of this species to South America. Additionally, previous evidence in support of a pre-Columbian introduction to South America relied on questionable identification of insect-based textile dyes. These uncertainties are significant because clearer knowledge of the history of O. ficus-indica introduction to South America could provide a more complete biological and ecological context to efforts at managing this species in its native and introduced ranges, particularly with respect to the threat posed by C. cactorum in North American and Argentinean plantations.