The fine silvery, golden and dark tea hairs that are commonly seen on the leaves and buds of Camellia Sinensis are called called down.
Perhaps through the history of Tea in recent China, the last few hundred years, I have found a reasonably close transliteration although mispronounced Chinese word of Xiamen dialect for "white down/hair" that is 白毫; Pe̍h-ōe-jī: pe̍h-ho. Or Pekoe in common English c.1819 (Chinese dictionary) now a common tea word.
Technically these are called tea trichomes but I will call them 'down'. These down are very much living, cellular extensions of the tea plant that provide a variety of functions to the tea bushel.
This is a naturally occurring phenomenon present in many different algae and plant forms including the Camellia Sinensis varietals. For the tea plant specifically the down are more prevalent around the new growth and especially dense over the apical shoot bud and its first neighbour, the first adjacent leaf.
Now this is an example of the incredible gift of nature up close:
Golden Tip Pure DianHong Yunnan, China
Look carefully at the fine golden down fully coating the tea bud.
Another example: the famous Baihao Yinzhen tea from China is also known as White Hair Silver Needle grown in the area of Zhenghe and Fuding in the Northern and North Eastern parts of Fujian Province. The genuine cultivars for white tea are a large leaf tea tree called Zhenghe Da Bai and Fuding Da Bai respectively.
The silvery white down on the tea buds and leaves are clearly visible. The tea will be picked according to precise rules before the buds open in early spring. Perfect conditions are sought after every spring to pick these downy delights.
Essentially these down increase the boundary between leaf and atmosphere. Their purpose are to protect against UV-damage, water evaporation, herbivore and pathogen attack.
These tea down are the very protective outfit for the young growth and with the right conditions and nutrient density the tea plant will escape pathogen attack.
This image shows the down all over the bud, under leaf and stem:
Hukalau White, Hawaii
It is in fact the catechins* and caffeine found in the tea plant that work as a secondary metabolite defence mechanism against oxidative stress, predator and pathogen attack and other environmental variables.
The silvery down that coats the tea leaf is the defence mechanism of the tea plants.
Perhaps you may first encounter these down in your own tea cup. When you make loose leaf artisan tea they will float on top of the tea liquor.
Some people claim there are great benefits in consumption of tea down. They are certainly harmless and provide a wonderful spectacle and spiritual connection.
* my next article will discuss what catechins are and how they are useful for us.