Jamaican nightshade is a prickly, perennial, invasive shrub in central and southern peninsular Florida. It was first seen in Florida in 1930 near St. Cloud, and has since been reported at several other locations in the state. Jamaican nightshade is primarily found in wooded habitats, where it can quickly become dominant in the understory, but it also occasionally grows in isolated patches in the open. Although the distribution of Jamaican nightshade does not appear to be rapidly expanding in Florida, land mangers should be made aware of the potential of this weed to establish at new sites, and initiate control efforts during the early stages of colonization at newly invaded sites.

Japanese hedgeparsley is an annual (or sometimes biennial) forb introduced from Eurasia and found throughout much of the eastern United States and parts of extreme southern Canada. In North America, Japanese hedgeparsley is commonly found in ruderal habitats, such as roadsides, railroad rights-of-way, forest edges, and urban waste spaces. This species has not yet been listed as a noxious invasive, but its expanding populations have caused concern in several Midwestern states. The primary threat from Japanese hedgeparsley is its vigorous growth habit, which creates dense patches, and its dispersal ability, facilitated by its clinging, burr-like fruits. Some confusion on identification exists within the Torilis genus, with similar species (particularly T. arvensis) frequently misidentified in herbaria and the literature. Here, we review aspects of the etymology, taxonomy, biology, distribution, and management of Japanese hedgeparsley with the objective of increasing awareness of the potential threat posed by this species and its closely related congeners.

Lesser celandine (Ranunculus ficaria) is an ephemeral perennial introduced to North America from Europe for ornamental use. This species is becoming widespread in shady, moist woodlands and lawns in the northern United States and southern Canada. Despite its invasive attributes, lesser celandine continues to be marketed by the nursery sector. A hardy and easy plant to grow, lesser celandine has a dense compact growth form that makes it ideal for border plantings and showy flowers that make it a desirable garden species for early spring color. The species easily escapes cultivation, colonizing primarily moist woodland habitats. Once established, lesser celandine creates a monoculture and is purported to displace native ephemeral species. Several factors make control of lesser celandine difficult, including a large root structure, which facilitates clonal reproduction and spread. The ephemerality of lesser celandine results in a relatively brief window in which to apply control measures. Land managers need to be aware of this common garden species as a potentially invasive weed and need to be able to differentiate it from the similar native marsh marigold. Effective management strategies are needed to protect native woodland understory species and biodiversity in natural and seminatural areas of affected regions.

There is evidence in the literature that a variety of logging practices may result in significant short and long-term changes to vegetation in the forest understory, however, these changes are still largely unknown for many forest types. The objective of this study was to determine the short-term effects of shelterwood logging on tree and non-arboreal plant species composition and diversity in both the understory and sapling strata within the Owain Lake Stand of old-growth red and eastern white pine located in Temagami, Ontario. The most significant changes were increases of white birch (800%), red maple (363%) and bracken fern (110%) in the understory. The most significant decreases within the understory occurred in mosses and liverworts (110%), Canada mayflower (49%) and starflower (28%). Bracken fern, red maple, and bush honeysuckle were the three most abundant species in the post-harvest understory plant community and will probably increase in their abundance under the present disturbed condition. A second shelterwood cut in 20 to 40 years may further facilitate an increase in these three species primarily by increasing light levels at the forest floor. All three species are very vigorous and are likely to dominate the forest understory until the upper canopy closes resulting in decreased light intensity at the forest floor.