Friends' News May 2012

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Photograph by Howard Rice

A green grove

Juliet Day

Friends’ News At the eastern end of the Glasshouse Range, a new green grove has been developed that extends the story of plant life before flowers: hardy ferns and cone-bearing coniferous trees predominate, survivors of some of the most ancient plant lineages on earth. When the Garden boundary was straightened up to meet the new machinery barn, this reunited the Cork Oak (Quercus suber) with its hybrid, the Fulham Oak (Quercus x hispanica ‘Fulhamensis’), and brought both back into the public domain. Peter Kerley and Paul Aston of the Demo & Display team quickly realised that the domed semi-evergreen canopies of the Oaks would provide the perfect, sheltered climate to plant up with ferns, tree ferns, and some early conifers. This would expand the theme of ‘life before flowers’, the subject of the small north-facing shady glasshouse tucked behind the main Range . The two curved benches that edge the paved area have been pulled apart to allow a winding path of bark chips to snake around the Cork Oaks and through the new planting. Longhoarded, salvaged tree rootballs (the biggest being the Robinia that blew down in the Gilbert Carter area around 2006) have been scattered into an informal stumpery, the rotting niches providing perfect footholds for maidenhair and hart’s tongue ferns.

Paul Aston

Once established, the area will have a very distinct feel – a green, almost aqueous grove of fronds, and notable for a total lack of colourful flowers. The plants are all survivors or

Fern prothallii, an intermediate stage.

descendants of some of the early plant lineages to evolve on land. These include the horsetails, and although they are the scourge of tidy-minded gardeners, we have included several Equisetum in the display, their expansionist tendencies curtailed by being grown in sunken pots. Ferns are a very ancient group of plants that appeared 200 million years before flowering plants and are far older than the land animals and dinosaurs. They are some of the earliest vascular plants with systems for transporting water and nutrients, but unlike other vascular plants, where the adult plant grows directly from the seed, ferns reproduce from spores in a circuitous process. Spores are released from the underside of fern fronds; if a spore finds suitable conditions, it will grow into a tiny heart-shaped intermediate plantlet called a prothallus, in which the male and female genetic material is separately held. If there is sufficient moisture for the sperm cells to swim to the female eggs, then fertilisation occurs and a complete mature fern grows. In propagating stock for the display, Paul found the recycled microwave take-away food containers created exactly the right conditions to ensure that this involved process ended up with mature plants! Although sheltered and shady, we will also install some irrigation to give short bursts of spray in the early morning and late evening from the borehole supply to ensure the moist conditions the ferns will need to proliferate. After the Carboniferous Age, when the great coal seams were laid down, few horsetails survived and the ferns had severely dwindled in variety. New plants emerged including wind-pollinated seed plants that produce naked seeds on woody scales gathered into

Paul Aston plants out. cone-like structures. We have included Maidenhair (Ginkgo biloba), Wollemi Pine (Wollemia nobilis) and the Monkey Puzzle (Araucaria augustifolia) in the display to provide structure but also to tell that next chapter in the story of plant evolution. By the end of the Jurassic era, insects and insect-pollinated flowering plants brought an explosion of colour, but this new planting takes us back to when the world was only green.

Juliet Day, Peter Kerley and Paul Aston

Giving in Memory The original fern courtyard at the eastern exit of the Glasshouse Range was developed with a generous gift from Mrs Jemima Atkinson and her family in memory of husband John, for whom the Garden became a ‘home from home’. It was thrilling to have the help once again of Mrs Atkinson in planting out some of the new ferns for the extended display. To make a gift to the Garden in memory or in celebration, please contact Juliet Day on 01223 762994 or jcd35@cam.ac.uk

Friends’ News – Issue 89 – May 2012


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