T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Elegia capensis (Horsetail restio)

Kingdom: Plantae
Subkingdom: Embryophyta
(unranked): Angiosperms
Division: Magnoliophyta
Class: Liliopsida
Subclass: Commelinidae
Order: Poales
Family: Restionaceae
Genre: Elegia
Species: E. capensis
Binomial name: Elegia capensis
Synonymy: Elegia verticillaris, Equisetum capense, Restio verticillaris, Restio verticillatus, Equisetum capense, Restio verticillaris, Restio verticillatus.
Common names. Horsetail restio, Broom Reed.

Elegia capensis is a restio (a group of plants within the Restionaceae family) native to South Africa. It is a tall, fast-growing, dark green, dioecious, caespitose (forming dense turfs) perennial growing up to 5m tall. The culms (stems) are like reeds, they grow from rhizomes underground, are fairly thick, with internodes like bamboo. At each node, there is a circle of long, sterile, needles branches in whorls. There are papery sheaths along the stems at the nodes. As the stem grows older, these sheaths become stiff and parchment-like and stand away from the stem. When the plants are nearly ready to flower, the sheaths fall off and leave the stems with a thin line and whorls of needle-like branches.
The male and female inflorescences develop at the top of the branches. Both male and female inflorescences are about 350 mm long. The actual flowers are small, white or greenish-yellow. The brown seeds resemble small nuts with wings.
The plants form a thick forest of stems and can eventually occupy quite a large space if the rhizomes are not kept in check.  

A culm with dense sterile verticillate branches radiating from a node.

The sheath has become stiff and parchment-like and is standing away from the stem.

Photo of a young plant showing the papery sheaths along the stems at the nodes.

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/