Japanese honeysuckle (Lonicera japonica Thunb.) is a twining semi-evergreen vine native to Japan, Korea and eastern China. Over the past 150 yr it has been introduced as an ornamental and become established in temperate and tropical regions worldwide. It was first discovered in Canada in 1976 in southwestern Ontario woodlands and has since been found growing without cultivation in 15 localities. While L. japonica does not occur very frequently in southern Ontario, climate change models suggest that it may become more abundant in this region. Its predominance elsewhere derives from morphological and physiological characteristics that allow it to be particularly successful in the edge habitats of fragmented landscapes. Through extensive vegetative propagation and competitive ability it occupies space which may otherwise host a diverse native flora. The plant has many uses in Asian medicine and is a popular ornamental, but has been prohibited in some regions due to its displacement of other species. A combination of cutting and foliar application of glyphosate has proven to be an effective control method in some circumstances. Planting of L. japonica should be discouraged and horticulturalists should consider alternative attractive vines. The spread of L. japonica should be monitored in Ontario and control of newly established populations should be considered to avoid costly large scale control in the future. Key words: Invasive species, Lonicera japonica, weed biology, climate change

Kudzu is reported for the first time in Canada. A population was found covering about 3500 m² on a bank above Lake Erie near the town of Leamington, Ontario. We detected high seed viability and germination rates but no evidence that the population has been expanding beyond this site. Nonetheless, we recommend that measures be taken to prevent its continued expansion.

1976. Evidence of microevolution in an escaped pear population. Can. J. Bot. 54: 2857-2867. A population of 87 wild pears (Pynis commrrr~is L.) of fruiting age, growing in a relatively homogeneous old field environment, was found to be highly variable. with coefficients of variation up to 40%. Generally, variability was greater in size than in meristic characters, in meristic characters than in shape characters, and floral traits were less variable than vegetative. Tree trunk core samples showed the population to have been founded circa 1905 to 1908, by three trees. Establishment ofprogeny began about 19 years later. The population is high in 1975 and still expanding logarithmically. Numerical taxonomic clustering techniques using morphological characters showed the population to contain two very diverse groups. Trees of both groups are of all age classes and are distributed randomly over the site. Trees phenetically like and unlike the oldest trees were analysed as to growth rates. Those trees similar to the oldest trees were significantly slower in growth rate than trees that were morphologically dissimilar. This suggests that natural selection is operating to remove the less fit genotype from the population.