Cyclobalanopsis myrsinifolia Seeds | Bamboo-leaved Oak

Bamboo-leaved Oak (Cyclobalanopsis myrsinifolia) with slender toothed evergreen leaves and small acorns in ringed cups — Bamboo-leaved Oak (*Cyclobalanopsis myrsinifolia*): Fagaceae, an evergreen oak of warm-temperate China whose narrow leaves and ringed acorn cups make it unmistakable.

LATIN NAME: Cyclobalanopsis myrsinifolia

COMMON NAME: Bamboo-Leaved Oak

Plant Profile

Bamboo-leaved oak is an evergreen tree, ten to twenty metres tall, with a dense, rounded crown and a trunk that is grey and smooth when young, roughening into shallow fissures with age. The leaves are the reason for the name: they are narrow, lance-shaped, six to twelve centimetres long and only two to three wide, with a toothed margin and a glossy, leathery surface, so that the canopy has the fine, rustling texture of a bamboo grove rather than the heaviness of a holly. New growth is pinkish bronze and flushes in spring, and old leaves fall in the second or third year.

The acorns are small, one and a half to two centimetres long, and they sit in cups marked with five to seven concentric rings of scale, which is the character that separates the ring-cupped oaks from the rest. They ripen in the first autumn after flowering and are taken quickly by rodents, jays and wild pigs. The flowers are inconspicuous catkins, produced in spring, and the tree is wind-pollinated. The species is native to the evergreen broadleaved forests of southern China, Japan, Korea and northern Vietnam, generally below a thousand metres, on acid, well-drained soils in warm, humid conditions. It is one of the characteristic trees of the lauriphyllous forest that once covered the lower hills of the Yangtze basin.

Science & Biotechnology

The ring-cupped oaks were long kept in their own genus, Cyclobalanopsis, on the strength of those concentric cup scales, but molecular work has shown that they sit inside Quercus as a distinct lineage, and most authorities now treat them as a subgenus. That reclassification matters for anyone working with the trees, because the literature uses both names and the two are not always cross-referenced. The group is thought to have originated in East Asia and to have spread into the tropical mountains, and it is one of the few evergreen oak lineages in the region. Studies of the species’ leaf anatomy describe the thick cuticle, the sunken stomata and the dense palisade tissue that make it a textbook sclerophyll.

The ecology of the tree has been studied in the context of the evergreen broadleaved forest that dominates southern China. It is a shade-tolerant species when young, establishing under a closed canopy and responding to gaps with faster growth, and it is one of the species that replaces pine in secondary succession on acid soils. Its acorns are dispersed mainly by scatter-hoarding rodents, which bury them in caches and lose a proportion, and the size of the acorn crop varies widely between years, a masting pattern that satiates seed predators in good years and starves them in poor ones. The tree forms ectomycorrhizal associations, and its roots support a distinctive fungal community.

Uses & Benefits

The wood is hard, dense and heavy, pale brown with a darker heart, and is used for tool handles, flooring, furniture and turned work, though the tree is rarely planted for timber. The acorns are edible after leaching, and in parts of southern China they have been used as a famine food and, more recently, as a minor wild crop for flour and starch. The tree is also planted as an evergreen shade tree in parks and along roads in warm-temperate cities, where its dense crown and tolerance of pruning make it useful.

In the garden, bamboo-leaved oak is a good evergreen specimen for a sheltered, acid site, and it can be clipped into a hedge or grown as a large shrub if space is limited. It is slower than the deciduous oaks and takes several years to establish, but it is long-lived and needs almost no attention once it is growing. Its narrow leaves and fine texture make it a good contrast to broad-leaved evergreens, and its tolerance of shade allows it to be used under taller trees. It is not suitable for exposed, windy sites or for shallow, chalky soils.

Growing from Seed

The acorn is recalcitrant and must be sown fresh, in autumn, as soon as it falls. It cannot be dried or stored for long. Sow it in a deep pot of loam, leaf mould and grit, with the acorn on its side and just covered, and keep it cool and moist. Germination takes four to eight weeks, and the radicle emerges first and drives straight down, so the pot must be deep. Protect the acorns from mice and squirrels, which will find them wherever they are.

Prick the seedlings out before the taproot reaches the bottom of the pot, and grow them on in a shaded frame for the first two years. Plant out in autumn into deep, acid, well-drained soil, in sun or part shade, with shelter from wind while the tree is young. Mulch with leaf mould and keep the ground clear of grass for the first three years. The tree is slow to start and then grows steadily at thirty to fifty centimetres a year, and it begins to fruit at about twelve years.

Our Take

A handsome evergreen oak for a mild, humid garden, with fine foliage and a long life ahead of it. Sow the acorns fresh and deep, and protect them from the squirrels.

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