Ask most people what an Assam tea bush actually is, and they name one of two things: the big-leaf wild bush Robert Bruce found near Sadiya, or, once they have read a label, some cross with the small-leaf China bush brought in to sharpen flavor. Both are real. Neither is the whole parentage. A third botanical type sits behind a working slice of the valley's modern clones, and this office has never certified it on its own terms: Cambod, formally Camellia sinensis var. lasiocalyx, a type native to the hill country running from Manipur down through Myanmar into Cambodia, Thailand, and Vietnam.

Six of Tocklai's numbered TV clones, TV23, TV25, TV26, TV27, TV28, and TV29, carry Cambod in their pedigree, and TV23 in particular sits near the theaflavin-heavy end of the valley's cup color, the pigment class this office already certifies as the difference between a pale infusion and a proper red-brown cup. If a garden card names one of those numbers, part of what is in your cup did not evolve in Assam, or even reach Assam by way of the wild stands near Sadiya. It arrived from across a border, on purpose, a little over a century ago.

The third type gets a name

Tea taxonomy has long recognized two working types: Camellia sinensis var. sinensis, the small, cold-hardy China bush, and var. assamica, the large-leaf Assam bush Bruce found growing wild. Cambod is the third, less-discussed member of that set, first described by the French botanist Jules Émile Planchon as Thea lasiocalyx, then folded into the genus Camellia by the colonial botanist George Watt near the turn of the twentieth century as Camellia thea var. lasiocalyx. For decades after that it sat in a taxonomic limbo, treated by different writers as a variety, a subspecies of assamica, or a mere cultivated form rather than a rank of its own.

That got settled, on paper at least, in 2016. Botanists A.P. Das and C. Ghosh published a formal new combination in the journal Pleione, Camellia sinensis var. lasiocalyx (G. Watt) A.P. Das & C. Ghosh, giving Cambod standing as its own named botanical variety rather than a footnote under assamica. Planters and traders had already been calling it "Cambod" or "Cambodi" for a century by then, after the country most associated with its stands; the 2016 paper mostly caught the science up to the trade name.

Watt worked mostly from dried, pressed specimens and the shape of the flower parts, the same evidence still used to sort a herbarium sheet today. What separates Cambod from its two better-known relatives is not leaf size (it runs medium, between the small China leaf and the broad Assam leaf) so much as the calyx and style: a hairier calyx than either of the other two, and a style that stays fused lower down before splitting into separate arms, the trait Watt's own species name records (lasio- hairy, -calyx the cup of sepals beneath the flower).

A range that runs past Assam's own border

This office has already certified the story of the wild Assam-type bush still standing, unplanted, in forest tracts near Sadiya and along the Assam-Arunachal-Nagaland stretch. Cambod's home ground is a different piece of the map. Botanist Pradip Baruah's 2017 survey of the region's wild tea, the same paper behind that Sadiya inventory, records unplanted stands of Assam and Cambod type together across "Assam, Manipur, Mizoram, Burma, Thailand, and the entire Annamite chain," the mountain spine that runs down the spine of Vietnam, Laos, and Cambodia. Genetic work on the wider assamica gene pool places its western edge along the Arakan mountains on the India-Myanmar border, taking in the Patkai and Lushai ranges, the Naga Hills, and Manipur, the same corridor.

So Cambod is not a Manipur plant alone. Manipur is one edge of a native range that runs an unbroken stretch of hill country from India's own northeastern border states down through Myanmar into the tea country of Cambodia, Thailand, and Vietnam. Wild tea growing in Manipur's forests today, tea that a small operation near Churachandpur now forages and sells rather than plants, sits at the Indian end of exactly this range, genuinely on Indian soil, and genuinely the same broad botanical race that also grows wild two countries away.

How a foreign stand ended up in a Tocklai nursery

Here is the part that does not match the brochure story. The Cambod germplasm actually sitting in Tocklai's breeding blocks, the material that eventually produced TV23 and its siblings, was not gathered from Manipur's own forests. A 2025 genetic study of the assamica gene pool, run by researchers including scientists at Tocklai itself, states plainly that the lasiocalyx-type germplasm in India's tea collections "were introduced into India from Indochina in the year 1917, or [are] progeny of these original introductions." The seed did not walk across the Manipur hills into an Assam garden. It was shipped in from further east, deliberately, as breeding material, and then bred forward for a full century inside Assam's own research station.

That is the twist worth sitting with. A type whose wild range genuinely reaches Indian soil, in Manipur's own forests, still entered the valley's cultivated gene pool as an import from abroad rather than a local gathering. The plant proves Assam's tea family runs wider than two lineages; the paperwork proves the valley reached outside its own borders, and outside India altogether, to actually put that third lineage to work.

Hybrid, or its own lineage? The genetics disagree with each other

For years, the working assumption among tea geneticists was that Cambod was not really a third type at all, just a natural hybrid swarm sitting between the other two. A 2016 genetic-marker study of south Indian tea germplasm found Cambod accessions carrying a mixed genetic signature of both China-type and Assam-type ancestry and read that as evidence the whole Cambod population arose from crossing between them, a hybrid rather than a lineage of its own.

The 2025 study that traced the 1917 Indochina introduction read the same kind of evidence differently, using a denser set of genetic markers (single nucleotide polymorphisms, SNPs, rather than the older AFLP method) across a wider sample. It grouped Cambod as a genuinely distinct population, one of several separate assamica lineages, not a blend of the other two: the genetic distance between Cambod and Indian assamica came out at Fst 0.197, and between Cambod and China-type var. sinensis at Fst 0.356, both differences the study treats as real and statistically solid, not noise. In plain terms, Fst measures how much of the genetic variation between two groups is explained by the groups being genuinely separate populations rather than one mixed pool; a Cambod-to-China gap nearly twice the Cambod-to-Assam gap is exactly what you would expect from three distinct lineages that share a common ancestor unevenly, not from Cambod being a simple 50-50 cross of the other two.

Nobody has fully closed this file, and the honest record is that the two studies used different tools on different sample sets and reached different conclusions about the same population. What has changed is the direction of travel: as the genetic tools have gotten sharper, the case for Cambod as its own lineage, not a hybrid smear between the other two, has gotten stronger, not weaker.

What Cambod parentage does to the cup

None of this is academic to the cup this office certifies. Cambod-descended clones carry a measurably different catechin profile from either parent type, and TV23 has been measured directly. A 2012 biochemical survey of Northeast Indian cultivars, the same study behind the catechin figures this office has already certified for the valley's clones generally, broke the comparison down by type:

Cambod sits in the middle, closer to Assam-type than to China-type but its own distinct point rather than a simple average of the two. TV23 itself, tested individually in the same survey, ran 220.6 milligrams of total catechin per gram of dry leaf, with epigallocatechin gallate (EGCG), the single largest catechin component and the main raw material theaflavins are built from during oxidation, measured at 116.1 milligrams per gram, over half of TV23's total catechin content on its own.

That matters because theaflavins, the pigments responsible for the bright coppery red in a proper cup, form when catechins like EGCG oxidize during manufacture; more of that raw material going in gives a clone more to work with. TV1, the valley's founding clone, released by 1950 and largely Assam-China parentage, already carries strong early-stage theaflavin formation on its own account, this office has certified that. What Cambod parentage in clones like TV23 adds is a second, chemically distinct route to the same result, bred and measured in its own right rather than as a footnote to the Assam-China story.

Three lineages, not two

The valley's tea does not trace to two lineages meeting in a garden. It traces to three: the wild Assam bush found near Sadiya, the smaller China stock crossed into it for flavor, and a third, Cambod, native to the same border-to-Indochina stretch, from Manipur down to Vietnam, whose actual breeding stock reached Tocklai as a deliberate import from Indochina in 1917 rather than a gathering from the wild stands on India's own side of that range. The taxonomists spent most of a century arguing over whether it was really its own type or a stray hybrid of the other two; the genetics now lean toward its own type. Either way, the next time an estate names TV23 or one of its Cambod-line siblings on a tea card, that number carries three continents of parentage compressed into it, not two.