Leaf longevity of Oxalis acetosella (Oxalidaceae) in the Catskill Mountains, New York, USA

Abstract

Leaf habit correlates with multiple physiological traits. Understanding ecophysiology is therefore dependent on knowledge of leaf habit. A variety of leaf habits exists within forest understory plant communities. Oxalis acetosella is one such understory plant and has long been considered a wintergreen, meaning that it keeps a set of leaves for one full year, replacing them with a new set during spring. To assess the leaf habit of O. acetosella and place it into a classification scheme of leaf habits, leaves of four populations of O. acetosella were repeatedly censused for two years in a northern hardwood forest of the Catskill Mountains, New York, USA. New leaves developed and old leaves senesced throughout the year, yielding a continual replacement of leaves and a summer peak in leaf number. Leaves that developed in the fall and winter had longer maximum life spans than leaves that developed during the summer. The name "seasonalgreen" is suggested to describe the continual development, senescence, and presence of leaves and annual peak in leaf number within O. acetosella. The functional significance of this leaf habit in this species and the possibility of its presence in other species deserve further study.

Leaf shape and venation pattern alter the support investments within leaf lamina in temperate species: a neglected source of leaf physiological differentiation?

“…The evergreen herbs A. europaeum and H. nobilis have a life span of 13 months. Although O. acetosella is also a wintergreen species, it continuously replaces leaves during the growing season (Tessier 2004), and the average leaf longevity of this species is therefore ≈6 months in our climate. As there can be important variation in leaf longevity within species groups (Diemer 1998), our estimates of Λ are crude.…”

The relative photosynthetic contribution of old and new fronds of the wintergreen fern Dryopteris carthusiana, Ontario, Canada1

“…Given the relatively high light levels in deciduous forests during the spring and fall and dark mid-summer conditions (Uemura 1994, Constabel andLieffers 1996), it is advantageous for an understory plant to maximize photosynthesis during periods when high-light conditions exist ). According to Tessier (2004), the potential to photosynthesize under high light conditions (by avoiding closed canopies) may be achieved in a number of ways including: spring ephemeral habit (plants which leaf out prior to canopy leaf out and senesce by mid-summer), wintergreen habit (leaves maintained for one full year and replaced in the late-spring), or evergreen habit (maintain leaves year round with leaf longevity exceeding one year) (see also : Landhä usser et al 1997, Tessier 2008; in fact the wintergreen habit has been categorized as a special case of evergreenness (Chabot and Hicks 1982). The latter two strategies are employed by different fern species in the deciduous forests of North America (Tessier 2001).…”

Old fronds serve as a vernal carbon source in the wintergreen fern Dryopteris intermedia (Aspleniaceae)

“…It will also help us to predict the impact of future changes to that environment on plant species, given changes in the global climate and more local habitat disruptions. Wintergreen species (those that develop a set of leaves in spring and keep them for 1 year until they are replaced with a new set) are of particular interest because they serve as an intermediate phenological strategy between deciduous species (those that keep green leaves only during the growing season) and evergreen species (those that keep green leaves for more than 1 calendar year) (Tessier, 2004). Removal of old wintergreen leaves prior to the development of new leaves did not affect new growth in Dryopteris crassirhizoma Nakai (Tani and Kudo, 2005) and Aristotelia chilensis (Mol.)…”