Cuticle micromorphology of Pinus krempfii Lecomte (Pinaceae) and additional species from southeast Asia

Cuticle micromorphology of the unusual Vietnamese pine, Pinus krempfii Leco mte, and three additional endemic southeast Asian species of Pinus L. (Pina ceae) is characterized for the first time. Taxa studied include (1) P. krem pfii, typically placed in its own subgenus Ducampopinus (Chevalier) Ferri: ex Little & Critchfield; (2) the endemic Vietnamese species Pinus dalatensi s Ferre and (3) the southeast Asian species Pinus kwantungensis Chun ex Tsi ang, both of subgenus Strobus; and (4) the widespread Asian species Pinus k esiya Royle ex Gordon of subgenus Pinus. The current and previous studies d emonstrate that the genus Pinus and its subgenera are delimited by unique c ombinations of cuticular characters, although some of these characters may occur individually in other conifers. Cuticular micromorphology supports ta xonomic assignment of P. krempfii to subgenus Strobus rather than to its ow n subgenus, a result that is also indicated by other anatomical studies and recent molecular studies. Sectional affinities of P. krempfii are usually with Parrya, subsection Krempfianae. An alternative classification of P. kr empfii with subsection Gerardianae can be supported by micromorphological c haracters including broad cuticular bridges between stomata, details of the intercellular flanges of the epidermal cells, and usually an amphistomatic stomatal distribution. Features of other Asian species studied are consist ent with their taxonomic assignments. The study demonstrates the utility of cuticle micromorphology to taxonomic delimitation within the family Pinace ae.