The cactus’s stem is a flat green pad; spines grow from the areoles, and the pads lean this way and that, like green palms pressed casually into the corner of a wall. Come summer, a thin yellow flower opens right beside the thorns.

A Heap of Green Palms

The cactus’s stem is a flat green pad with areoles and hard spines along the edges, leaning this way and that—like green palms pressed casually into the corner of a wall. In summer, a thin yellow flower opens right beside the thorns.

The part that looks like a leaf is not a leaf at all but a stem—its leaves long ago turned into spines on the areoles. A plant’s name and what it actually grows are often two different things.

— Botany Notes, self-inscription —

Bristling with spines, no one draws near;

yet a yellow flower lights the thorns.

The Spines Are Its Leftover Leaves

The cactus has reduced all its leaves to spines, and the green stems do the photosynthesis. This both cuts water loss and turns the spines into defense; the dense fuzz on the areoles can also gather a little dew at dawn.

Its body has thus become a small reservoir: the stems are filled with mucilaginous tissue, swelling with water in the wet season and drawing it down slowly through drought. A cactus’s plumpness writes how much water it has drunk lately.

A Foreign Guest of the Late Ming

It reached China around the late Ming dynasty; when old books first recorded it, the name was already xianrenzhang (“cactus palm”)—the Chinese gave this never-seen plant a very Chinese name.

Today, on southern seaside sands, whole stretches of it grow into thorn hedges keeping watch for the house. It needs no fussing; it simply stands itself into a wall.

• How to know it: Evergreen succulent shrub; stem segments flat and green, areoles bearing hard spines; flowers yellow; berries purplish-red; blooms summer.
• Season: Grows and blooms in warm seasons; southern summer flowering heaviest; growth slows in cold autumn and winter.
• Caution: Wear thick gloves to move or prune—fine bristles are hard to remove from skin; peel and de-spine fruit thoroughly before eating.

From Hedge to Fruit

The cactus serves as courtyard and hedge plant: drought-tolerant, poor-soil-tolerant, wind-breaking; a pad planted in the ground lives. When ripe, the fruit turns purplish-red, and once de-spined and peeled it is clear, sweet, and juicy—in the south some eat it as fruit.

Pruning and fruit-picking both call for thick gloves: the fine spines are nearly impossible to get out once they stick. It guards itself thoroughly, and teaches everyone who would approach it to be careful first.

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Keywords: cactus · succulent stem · hedge · drought tolerance