Invasive plants can alter nutrient cycling rates, because the leaves of many invasive species decay more quickly than those of native plants. Pyrus calleryana (Callery pear) is a relatively new woody invader in the eastern USA that rapidly colonizes open and disturbed areas. Invasive woody plants can alter forest nutrient cycling, yet the leaf decomposition rates of P. calleryana have not been previously determined. In this study, Pyrus calleryana leaf decomposition rates were compared against two widely distributed native trees, Acer rubrum (red maple) and Platanus occidentalis (American sycamore), with different levels of nitrogen (N), carbon (C):N, lignin, and lignin:N. It was also compared to that of the invasive shrub Amur honeysuckle (Lonicera maackii), which is known to have very fast decomposition rates. Litter bags were placed in four locations in a Callery pear-dominated stand in northern Kentucky in November 2014 and sampled at 3, 90, 12, and 18 mo. Dry weight and %N measurements were fit to a single exponential decay equation. Mass and N loss of P. calleryana leaf litter were both similar to those of A. rubrum, and they were lower than those of L. maackii; however, lignin and lignin:N levels were most similar to L. maackii. Platanus occidentalis decayed very slowly and immobilized rather than mineralized N. Pyrus calleryana is thus not predicted to greatly alter leaf litter decomposition in invaded forests, although litter decomposition dynamics might be different in mixtures with native species and in other locations.

Schinus terebinthifolius Raddi (Anacardiaceae) is a pioneer tropical species that has been largely used in Brazil for land restoration. The species occurrence encompasses inland ecosystems such as the neotropical savanna (cerrado sensu stricto; Cerrado domain) through coastal ecosystems such as mangroves and the restinga (Atlantic Forest domain), all of which are characterized by environmental factors that highly contrast with one another. We analyzed the leaf anatomy of S. terebinthifolius populations from those three ecosystems aiming to verify whether any particular trait would provide the species with foliar anatomical plasticity, thereby enabling it to adapt to such environmentally disparate areas. We found that thickness of the leaf blade, adaxial palisade parenchyma, and spongy parenchyma differed significantly among the three ecosystems. The population from the restinga, an open, coastal ecosystem subjected to high light incidence, showed the highest means for these variables, followed by the populations from mangrove and cerrado. Leaf blade thickness in the restinga population was higher due mainly to increased palisade parenchyma thickness. The adaxial palisade parenchyma thickness in mangrove individuals was more than double the one in the cerrado population. The abaxial palisade parenchyma thickness showed no difference between the mangrove and restinga populations, yet in those two it was higher than in the cerrado population. Schinus terebinthifolius was revealed to have high potential of acclimating to different ecosystems, owing to a high capacity of developing anatomical responses to distinct stress conditions imposed by the surrounding environment, which confirms the species high phenotypic plasticity. Such high capacity of acclimating to contrasting environmental conditions by means of modulating the thickness of different leaf tissues could provide the species with an adaptive advantage in a climate-change scenario.

Flowers consist of four whorls of organs (sepals, petals, stamens, and carpels), each expressing unique characteristics. In floral homeotic mutants, organs develop abnormally, and floral organs of one whorl express characteristics of another whorl. Much of our current understanding of the development of floral organs has been based on studies of floral homeotic mutants. In the homeotic mutant crinkle-petal (cp) of Clarkia tembloriensis, previous investigations demonstrated that the cp petal is a hybrid organ combining characteristics of sepals and petals. This investigation extends those studies with a comparative anatomical study of trichomes, guard cells, and marginal epidermal cells in wild-type (WT) sepals, WT petals, and cp petals. The aim was to determine if cp petals exhibit a hybrid epidermal anatomy of WT sepals and WT petals. Floral buds 1 day pre-anthesis and flowers 1 day post-anthesis were collected and prepared for light microscopy or scanning electron microscopy. Trichomes and guard cell pairs were described and counted, and marginal cells were observed and described. This anatomical study of trichomes, guard cells, and marginal cells demonstrated that cp petals of C. tembloriensis combine characteristics of both WT sepals and WT petals. These results provide further support for the hybrid nature of cp petals in Clarkia tembloriensis.

This work details the structure and composition of the woody plant community of a gallery forest located in the La Silla River, between Monterrey and Guadalupe urban areas in Nuevo León, Mexico. For the analysis, the woody vegetation was categorized into upper and lower strata. The upper stratum maximum height was 38 m, and the canopy cover was 100%. The canopy consisted of 22 species from 16 families, of which seven species represented 82.3% of the importance value index (IV); Taxodium huegelii had the highest IV (34.32%). The lower stratum maximum height was 2.5 m, and the cover was 48%. Thirteen species from 10 families were identified, five of which reached 81.3% of the IV; Ricinus communis had the highest IV (23.42%). The plant community diversity was 3.8 and 2.29, based on Margalef and Shannon indices, respectively. As one finding in the present study, it can be stated that the main threat is the presence of widely distributed exotic species such as Ricinus communis and Leucaena leucocephala, with high importance values. However, the presence of a well-established tree stratum, as well as the presence of species typical of the gallery forest, suggest a good state of conservation of this gallery forest. The present results highlight the importance of studying the composition, structure, and diversity, taking into consideration the flora of floristic provinces, as an analytic strategy for the diagnosis of riparian lentic community health.

Euterpe oleracea presents long leaves with divisions in the blade frequently referred to as leaflets or pinnae, as if they were compound. The purpose of this article is to present the first leaf ontogeny study for this species. Buds of dissected E. oleracea were classified according to their size and morphology and examined under scanning electron and light microscopy. The youngest leaf primordia are conical. The first foldings in the leaf blade appear in primordia ca. 0.8 mm in length and already have procambium. When young leaves reach 1.5 mm long, these plications separate from one another. Segments change their orientation throughout leaf development. Leaf blade in E. oleracea is initially entire (nonplicate), becoming plicate at a later stage, and plications separate from each other as a final step. This developmental process has some similarities with what is observed in other palm species. According to early stages of the leaf ontogeny, these plants have simple pinnatisect and not compound pinnate leaves. The use of terminology such as “leaflets” or “pinnae” is incongruent with simple leaves, and we recommend that adult leaf blade subdivisions of Arecaceae should be called “leaf segments” instead. This work contributed to the understanding of histological changes during palm leaf development, being a contemporary report on both histological and micromorphological study on palm leaf ontogeny.

The Phallales order has common names that are used to define groups based on basidiome shapes, such as Clathroid, Phalloid, and Lysuroid. However, up to now, there is no systematic and detailed information to define these and other basidiome shapes. New systematic definitions with notes on generic morphology and new nomenclatures are proposed to standardize the concepts related to the morphology of Phallales fungi, with illustrations for the main genres. In addition to the Clathroid, Laternoid, Lysuroid, and Phalloid forms, we proposed the division of the Clathroid type into two subdivisions (Lattice Clathroid and Columnar Clathroid) and the insertion of three new types of shape: Arachnoid, Floweroid, and Truffoid. We are also proposing a checklist and an identification key for all the species of Phallales in Brazil.