Variation of cuticle micromorphology of Metasequoia glyptostroboides (Taxodiaceae)

Leaf cuticle micromorphology of Metasequoia glyptostroboides Hu & W. C. Che ng was studied with SEM using samples collected from its natural population in south-central China and cultivated trees in Nanjing City. The cuticle c haracters from both natural and cultivated trees living in different enviro nments allowed us to re-evaluate taxonomic values of certain cuticular char acters and to assess their relationships with environmental factors and the degree of tree maturity. External and internal cuticular features of both adaxial (upper) and abaxial (lower) leaf surfaces revealed the following: ( 1) Cuticle micromorphology of M. glyptostroboides is distinct among Taxodia ceae, but that variation does not exceed the range of this family. (2) Exce pt for an isolated tree outside the Metasequoia valley, the cuticular featu res displayed by individual trees from the main Metasequoia groves demonstr ate a high degree of uniformity, which is in congruence with previous obser vations on the low population variability at the gross morphology level. (3 ) Cuticular characters of grafted Metasequoia trees living in different env ironments are identical to those of their original trees, indicating that n o cuticular character of this species could be regarded as an environmental indicator. (4) Recognition of some unique cuticular features in a Metasequ oia tree in an isolated location may lead to a rare source for increasing t he variation of this endangered species. (C) 2001 The Linnean Society of Lo ndon.