Hesperoyucca whipplei – a unique symbiotic existence

Yucca Seeds_01

I had never seen the seeds of a yucca before. It was surprising to see a smattering of jet-black seeds with such a contrast to the bare, dusty, cracked tan soil of our local chaparral. The seeds are beautiful, flat, textured and a bit shimmery.

The seed pods of the yucca plant are equally unique, and consist of four-chambered pods. Each pod is covered by a network of fibers, which crack as they dry to disperse dozens of seeds below. The fibers hold in place a stack of seeds, it seems 40-50 seeds. I thought it might be interesting to try and germinate the seeds, but upon further research, I learned that yucca seeds take anywhere between a month and a year to germinate (beyond my time frame for now), with continuous optimal conditions. No wonder there aren’t many yucca plants around the hills. Yucca Seeds_03

Not only is their germination slow and specific, these yucca plants only flower once in their life and then die. Additionally, the yucca is only pollinated by the Tegeticula maculata moth, which lays its eggs solely in the seedpod of this plant. So specific! The moth collects pollen sacks at night, and then forms them into a ball. She will then lay her eggs into the ovary wall of the female flowers, and rub the ball of pollen in this ovary, to ensure the plant will produce seeds for her young to eat. Some of the seeds I collected are more like seed conglomerates, a stack of seeds that has never been separated. They have holes eaten through them that must be from the larvae of the Tegeticula maculata.

yucca_04

 

The plant has many uses for the indigenous people of this region, including soap, cordage from the leaves, seeds as medicine for skin problems, and the heart of the plant as an important food. Despite its touchy reproductive habits, once established the yuccas are incredibly hardy, and are very resistant to fire and drought. I never realized that these seemingly indestructible, spiky and uninviting plants occupy such a delicate ecological niche in our hills.Yucca Seeds_02

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