Yucca glauca
(Narrowleaf, Soapweed yucca)
The inflorescence, a raceme, surrounds the top of the stem. Its size can vary a lot, from 30 cm to 200 cm.
Flowers bloom on short pedicels. They're close together and droop, so they can look a bit like harness bells.
Each flower has one style and 6 stamens.
A single species of moth, the yucca moth (Tegeticulla yuccasella), pollinates the flowers. That makes Y. glauca depended on the moth. But it's a co-dependence.
While pollinating, the moth lays eggs in the plant's ovary. As the plant produces seeds, the larvae hatch and eat some of the seeds -- their only source of food.
The co-dependence has some odd effects. The moths don't pollinate accidentally, they do it intentionally.
They're (as in the species) careful not to lay too many eggs in one plant so their larvae can eat enough and leave plenty of seeds keep Y. glauca in business.
If too many larvae hatch in one flower, the flower won't bloom.
The relationship has hung on for tens of millions of years and it's fascinating. You can read an eloquent description of it on the Cool Green Science blog.
The seeds (and moth larvae) grow in hard, brown, oblong fruits.
The fruits are divided into chambers, called locules. The seeds stack up in the locules like coins in a dispenser.
When the seeds are ready, the dry fruit splits open and the seeds drop to the ground or get carried off by wind.
Y. glauca can also reproduce without the bother of pollination. It's caudex and rhizomes can sprout new rosettes.
It sends out rhizomes like horizontal branches underground. It takes a few years, but the rhizomes can grow buds which extend to the surface and grow leaves to start a new plant.
