(American Journal of Botany. ;91:0.)
© Botanical Society of America, Inc.
Mosses and Mortar
Using novel substrates with a clear history of introduction as a means of tracking immigration yields interesting descriptive data in a study by Miller and McDaniel. In 1935 the construction of an 8-km roadway on Whiteface Mountain in the Adirondacks of New York State (see front cover) involved the introduction of calcium-rich mortar into a habitat lacking calcium-rich sites. The authors found that between 1935 and their studies in 1997/1998 moss species richness increased by 50% over that in control areas. Thus, approximately one new species arrived and settled per year through dispersal from places at least 5-10 km distant.
(see p. 1173)
A paper in this issue by Belmonte and Vil;aga tackles a previously unaddressed problem=mhow the atmospheric abundance and diversity of pollen of non-native plants affects human health.The authors monitored seven Spanish Mediterranean localities over 13 years, finding an increase in total numbers of airborne allergenic pollen and in duration of allergenic susceptibility. Their findings relate to global environmental change, which is coincident with a documented increase in human allergy during the past 50 years.
(see p. 1243)
The European dwarf palm Chamaerops humilis is the only flowering plant investigated thus far whose leaves produce volatile organic compounds (VOCs) that attract pollinators during flowering. In fact, the leaves attract a species-specific pollinating weevil, while the flowers are scentless. In order to find the site of production Caissard et al. employed VOC extraction of leaf parts, histochemical techniques, and electron microscopy to visualize cell compartments that might contain the compounds. They found that the whole leaf is responsible for VOC emission and offer interesting insights into scent production and emission phenomena.
(see p. 1190)
Primack et al. take a creative approach to measuring changes in phenology as a result of climate change. They used herbarium samples to detect changes in the flowering phenology of woody plants. Their data set is particularly compelling because it makes a comparison between living plants and herbarium specimens of those same individuals. Specifically, in 2003 they sampled 229 living plants at the Arnold Arboretum in Boston, Massachusetts, USA and compared that data with 372 records of flowering times from 1885 to 2002 made on herbarium samples from those plants. They found a pattern of earlier flowering associated with the 1.5;dgC rise in Boston's temperature during this period.
(see p. 1260)
