We tested the hypothesis that functional attributes of living
leaves provide a basis for predicting the decomposition rate of leaf
litter. The data were obtained from standardized screening tests on
38 British herbaceous species. Graminoid monocots had physically
tougher leaves with higher silicon contents than did herbaceous
dicots, and this corresponded with the lesser decomposibility of the
former. Total base content of living leaves was a good predictor of
litter decomposition rate, but the evolutionary and ecological basis
for this relationship appeared to differ between graminoid monocots
and herbaceous dicots. In the monocots, litter decomposition rate was
strongly predicted by leaf potassium content, which appeared to
reflect other growth-related plant attributes such as seedling
maximum relative growth rate, foliar nitrogen and phosphorus content,
specific leaf area and short leaf lifespan. In the dicots the
relationship between total leaf base content and litter decomposition
rate was not unambiguously explained by growth-related leaf
attributes, possibly because of the considerable calcium uptake by
dicots, which varies according to calcium availability in the
soil.