Physical and anatomical variations in culm characteristics of Pseudoxytenanthera bourdillonii (Gamble) H.B.Naithani – a lesser studied endemic bamboo in the Western Ghats, Kerala

Pseudoxytenanthera bourdillonii (Gamble) H.B.Naithani, locally known as “Arayambu”, represents one of the lesser-known bamboo species in the Western Ghats region of Kerala (restricted to Palakkad, Thrissur, Idukki and Malappuram districts). The present study evaluated physical and anatomical properties of this species in cluding fibre characters across various culm height. Ex perimental methods outlined in IS 6874 (2008) were used for moisture content and basic density studies. Franklin method was adopted for fibre maceration. It was observed that the moisture content consistently showed a decreasing trend from bottom to top whereas the basic density found a reverse trend. The plant volumetric shrinkage bottom to top. Additionally, the vessel diameter was high er in inner compared to middle and outer part. There was a significant difference in parenchyma diameter between outer and inner portion. Despite having a runkel ratio greater than one, other fibre parameters of P. bourdillonii make it suitable for pulping and remains a favorable option for handicraft sector owing to its non-thorny nature substantial intermodal length, and attractive golden yellow color of both the culm and culm sheath. However, P. bourdillonii culms of two-year age group is less preferred for high strength demanding purpose due to high moisture content and lower basic density. reaches its peak in the middle of the culm. The highest fibre length (2.65 ± 0.16 mm) was noticed in the middle slivers taken from the bottom portion of culm. The fibre width and lumen width of the bottom part showed a significant difference compared to middle and top culm (P< 0.05). There was no significant difference in wall thickness between height position and radial position. The average Runkel ratio found to be greater than one. Vas cular bundle numbers showed an increasing trend from