Wood structural diversity among Himalayan rhododendron

Abstract

The wood anatomy of nine species of Himalayan Rhododendron is compared. All share the characters: growth rings present, but indistinct; pores evenly distributed, numerous; intervessel pits alternate; perforation plates scalariform with 10 to 30 bars; wood parenchyma diffuse or diffuse-in-aggregates; rays heterogeneous uniseriate and multiseriate. However, pore size, occurrence of spiral thickenings and frequency of multiseriate rays are variable among the species studied. Our investigation shows that these characters vary according to the habit of plants. The woods of trees have wider vessels, distinct spirals in both vessels and fibre-tracheids, and numerous multiseriate rays, while those of shrubs have narrower vessels with indistinct or restricted spirals and less frequent multiseriate rays.