Which Styrax Species Produce Resin? A Genus-Wide Survey

The genus Styrax (family Styracaceae) comprises roughly 130 species of trees and shrubs distributed across eastern and southeastern Asia, the Americas, and a single Mediterranean outlier, yet only a handful are documented sources of commercial resin. Benzoin, a fragrant balsamic exudate rich in esters of benzoic and cinnamic acid, is produced almost exclusively by two Southeast Asian species: Styrax tonkinensis, native to Laos and northern Vietnam and tapped for Siam benzoin, and Styrax benzoin together with the closely related Styrax paralleloneurus, both native to Sumatra and tapped for Sumatra benzoin. A third species, the Mediterranean Styrax officinalis, gave the genus its name and its historical link to the resin known as storax, though botanical accounts describe its actual resin yield as sparse. The remaining Styrax species, including the widely planted ornamental Styrax japonicus, are not documented resin sources at all.

The genus at a glance

Styrax belongs to Styracaceae, a small family of about a dozen genera concentrated in warm temperate and tropical Asia and the Americas. Species range from understorey shrubs to canopy trees over thirty metres tall, most bearing white, bell-shaped flowers in spring and a hard, one-seeded drupe. The genus has a classic disjunct distribution: a large East and Southeast Asian block, a second centre in the Americas running from the southeastern United States down through Mexico and Central America into South America, and a single Old World outlier in the Mediterranean and Levant.

Resin production in Styrax is not spontaneous the way it is in gum-resin trees such as the frankincense and myrrh genera. The balsam forms as a wound response: a deliberate cut or scrape in the bark triggers secretory tissue to exude a sticky liquid that hardens into solid tears on contact with air, a process described in detail in The Styrax Tree. Most Styrax species, when wounded, produce only a thin, unremarkable sap. Commercial exploitation has concentrated on the few species whose wound exudate is abundant, aromatic and stable enough to dry into blocks.

Which species actually yield commercial resin?

Botanical surveys and trade literature converge on a short list. Two Sumatran species, S. benzoin and S. paralleloneurus, supply Sumatra benzoin; one mainland Southeast Asian species, S. tonkinensis, supplies Siam benzoin. Beyond this pair of source regions, no other Styrax species is tapped at commercial scale today.

Historical records mention limited, localized use of resin from S. officinalis around the eastern Mediterranean, but that trade had largely lapsed by the twentieth century, partly because the tree’s yield is low and partly because a taxonomically unrelated tree, Liquidambar orientalis, supplied the far more productive resin that continued to be sold as storax in European and Middle Eastern markets. That naming overlap between Styrax and Liquidambar products is a recurring source of confusion, unpacked at length in Benzoin vs Styrax (Storax).

Styrax benzoin and Styrax paralleloneurus: the Sumatra source

Styrax benzoin Dryander is a mid-sized tree native to the lowland and hill forests of Sumatra, cultivated in smallholder agroforestry plots rather than wild-harvested. Styrax paralleloneurus Perkins, found in the same highland districts of West Sumatra, is closely related, and in practice its resin is rarely separated from that of S. benzoin in the trade; both feed into the material sold commercially as Sumatra benzoin. Farmers tap the trees by making shallow incisions in the bark and returning months later to collect the hardened balsam, which is then sorted by colour and purity into commercial grades.

Styrax tonkinensis: the Siam source

Styrax tonkinensis (Pierre) Craib ex Hartwich grows across upland Laos, northern Vietnam, and adjoining parts of Thailand and southern China. It is a fast-growing pioneer species, often the first tree to colonize cleared land, which made it well suited to the shifting-cultivation cycles of the Lao uplands. Its resin, sold as Siam benzoin, is generally paler and considered finer than the Sumatran material, with a sweeter, more vanilla-like character that has made it the preferred grade for fine perfumery.

What happened to Styrax officinalis, the tree that named the genus?

Styrax officinalis L. grows as a shrub or small tree across Greece, Turkey, the Levant and parts of North Africa, and it was the species early European naturalists had in mind when they named the genus and linked it to the ancient storax of Mediterranean trade. Modern accounts, however, describe its resin yield as sparse and its exudate as difficult to work into a stable commercial product.

By the time systematic trade records exist, the storax reaching European ports was overwhelmingly the product of Liquidambar orientalis, an unrelated tree of southwestern Anatolia. The story of how S. officinalis lent its name to a resin it barely supplied is told in Styrax officinalis: the Mediterranean Shrub That Gave Styrax Its Name.

Why doesn’t Styrax japonicus produce resin?

Styrax japonicus Siebold & Zucc., the Japanese snowbell, is one of the most widely planted Styrax species outside its native range, grown across temperate gardens for its drooping white flowers rather than any resin. There is no documented tradition of tapping it, and nothing in the botanical or trade literature identifies it as a resin source.

Its case illustrates a broader point about the genus: ornamental popularity and wide cultivation are unrelated to resin productivity, a trait that appears confined to a handful of species within specific lineages of the genus.

What does the resin from each species smell like?

The three commercially relevant Styrax resins share a family resemblance built on the same core chemistry but differ in emphasis. All are dominated by esters of benzoic acid and cinnamic acid, which give the characteristic warm, balsamic, faintly sweet base note. Sumatra benzoin, from S. benzoin and S. paralleloneurus, tends to read as more spicy-balsamic, with a resinous edge. Siam benzoin, from S. tonkinensis, is generally described as sweeter and closer to vanilla. The difference between the two is compared directly, molecule by molecule, in Siam vs Sumatra Benzoin.

A genus-wide summary

Of roughly 130 species in the genus, then, only three are tapped for resin today, and a fourth survives mainly as a historical footnote. The pattern is worth remembering whenever storax or benzoin appears in an old text: the name may point to a Styrax tree, a Liquidambar tree, or a trade term that outlived the botany it originally described.

• styrax
• botany
• benzoin
• species
• storax