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Mike's Blog - Day 258

The return of the wild orchid Epipactis helleborine, the Broad-leaved Helleborine which we had on Day 130.

Here it is again in close-up.

The numbers are increasing every year and we have mown round them to leave their seed heads to disperse the seed. The seed is very fine, like dust.

Orchid seed is unusual.

Peas, conkers, acorns and so on are clearly what you would call a seed. They have a store of food for the tiny embryo inside. This food supply supports the embryo as it germinates and begins to grow, feeding it until it can develop roots to draw nutrients and water from the soil and proper leaves to get energy from the sun.

The orchid seed has no such food supply and if you sowed some of the seed in a pot it’s unlikely to grow. It can be germinated in special nutrient rich cultures and grown on in flasks until it can make the transition to getting its own food. So, how do these orchid seeds manage to germinate on their own without their own food supply ?

The answer is fungi – in the soil growing with the orchids are associated fungi, the fungi “roots”  (mycorrhiza) grow with the plant roots and help the plant get some of the water and  nutrients it needs. In a way these are an extension of the plants own root system. If the orchid seeds land on the ground where these mycorrhizal fungi exist then its these supply the seed with what it needs to grow.

Different species of Orchid, and other plants, all have their associated mycorrhiza.

This is what was so exciting when the Bee orchid was discovered locally (Day 111). If its growing then it must also have the mycorrhiza in the soil with it. This means that although the orchid itself might not come back, or lie dormant in 2021, it might have seeded around and a colony of bee orchids and its mycorrhiza might develop.

What with bacteria turning water orange, algae growing on trees and invisible mycorrhiza feeding orchid seeds and other plants there is a lot going on at a very microscopic level in the garden. Amazing really.