Libocedrus bidwillii

Features

Tree 25(-30) m tall and 1.0-1.5 m d.b.h., or a shrub in open conditions, evergreen, monoecious. Bark thin, scaly, greyish-brown, exfoliating in longitudinal strips. Branches long, spreading or ascending, arranged in dense tufts above each other, forming a pyramidal crown in young trees, conical or irregular with a clear bole in old trees. Foliage flattened sprays in young trees, in old trees more irregular and ascending, ultimate branchlets subopposite to alternate, 5-40 mm long, entirely covered with leaves, changing with age of plant from flattened to ± quadrangular, persistent. Leaves decussate, on lateral branchlets, short, decurrent, imbricate, dimorphic in young trees, facials small, rhombic, 1.5-2.0 × 1..0 mm, apiculate to acute, appressed, partly covered at base by larger 2.0-6.0 × 1.5-2.5 mm, divergent, bilaterally flattened, slightly curved laterals with entire margins and free apices, leaves on mature trees smaller, nearly monomorphic; amphistomatic, stomata on facials at base, on laterals much reduced on adaxial side, abaxially in a short, conspicuous band of irregularly but densely arranged stomata, adaxially dull dark green or yellow-green with whitish-green stomatal band, bearing a single resin cavity, eglandular. Pollen cones terminal, solitary, 2.5-5.0 mm, subglobose to ovoid, yellowish-green maturing light brown; microsporophylls decussate, 8-14, peltate, margins entire, bearing 4 abaxial yellow, microsporangia containing spherical pollen. Seed cones terminal on branchlets with monomorphic leaves of equal size, initially consisting of 2 decussate pairs of acute, 3-4 mm long, spreading bracts subtended by 4-5 similar but gradually smaller leaf pairs, the upper pair developing within one growing season to become thinly woody, together forming a cone 8-12 mm long. Bract-scale complexes 7-10 mm long, ± finely rugose, recurved in upper half above the abaxially exserting bract, subtended by the lower, smaller (3-4 mm long) less modified pair. Ovules 4, erect. alternating with each fertile bract. Seeds 2-4, 2-3 mm long, ovoid, flattened, with an acute apex, brown, with a whitish hilum and 2 opposite, thin, unequal, membranous wings, smaller 1 mm wide, larger, irregularly oval-oblong, 4-5 × 2.3 mm, yellowish brown. Cotyledons 2, juveniles leaves only on seedlings, ± acicular, on lower stem in whorls of 4 but soon decussate, bilaterally flattened, acuminate, the facials only slightly smaller, transitional leaves prevalent through much of life of young trees.