Visit to Kew by the Indoor and Tropical Fern Group

Twenty-five members of the IATFG and their friends met at the Elizabeth Gate at Kew Gardens on the morning of Saturday 25 March 2023. Alice Taylor had arranged a behind-the-scenes visit to the Kew ‘ranges’. These glasshouses, which are not open to the public, contain a huge collection of ferns in closely controlled environments of temperature, light and humidity. Other houses contain orchids and other tropical plants. The purpose of the collections has previously been to support research but there are now less requests for tissue than used to be the case. So, maintenance of the collections for the purposes of education and conservation is becoming more important in justifying the continuing support for the houses. This is especially so since the huge increase in the price of energy.

We visited one house for tropical ferns and another for those from temperate regions. In particular, a misting system was in action somewhere in the glasshouse at all times. This system used deionised water (reverse osmosis) so as to avoid the problem of limescale blocking the spray nozzles, as we had seen in the Belfast Tropical Ravine last year. A feature of many of the tropical ferns is a shallow root-run which makes accommodating them in seed trays easy, but which requires a regimen of frequent watering, which was generally carried out at least once per day using hosepipes. The minimum daytime temperature of the tropical house was 20 ºC with venting at 24 ºC. The minimum night time temperature was 18 ºC. In the temperate house the daytime minimum daytime was set at 17 ºC with venting at 18 ºC and the minimum night-time at 11 ºC. Both houses were maintained at 65 %RH.

In this environment familiar ferns grew to enormous proportions and ones not familiar to us thrived (Figure 1). In particular, there was a fine collection of Drynaria which Alice was trying to move from being tray-based into hanging baskets. Her method of propagation was interesting in that she would lay a tray of compost next to a plant with an advancing rhizome and let the rhizome grow over the new tray for several months. Then she would divide that rhizome from the mother plant and separate the trays without disturbing the roots of either the mother or the new plant. There were many Davallia and other epiphytes growing on pieces of cork bark hanging on the wall and a fine collection of Selaginella in seed trays. Along one side of the house were specimens of Marattiaceae with fronds of 3–4 m length. Unfortunately, the species were not

identified on the labels.

After lunch the group broke up and visited the Palm House, Temperate House and the Princess of Wales House, which contains the main tropical fern collection open to the public. The ferns there were, again, very large and well-cared for with specimens of Drynaria splendens and Platycerium superbum that most of us could only dream of growing (Figure 2). Macrothelypteris torresiana had self-sown around the beds and created a very lush environment. The collection there is well-worth visiting again, probably on a weekday when there are fewer visitors heading for the orchid displays and when there is time and space for closer examination of the plants.

The Temperate House was rebuilt and restocked several years ago and, at that time, looked rather empty when finished. Over the past few years, the trees and shrubs in there have grown well and the environment was very lush. A grove of, probably, ten Sphaeropteris medullaris had become well-established and created a very exotic atmosphere (Figure 3). The Palm House contained a few ferns, including Microsorum punctatum, an unidentified Blechnum, probably Blechnum appendiculatum, and an

interesting Tectaria (Figures 4 & 5).

The day was enjoyed by all and it is hoped to repeat the visit in a few years’ time.

PETER BLAKE

Peter became interested in tropical ferns whilst making regular trips to India in the 1990s and 2000s. He retired from the NHS in 2012 and was able to develop his interest in growing tropical ferns from spores. He now lives in Norwich where he can provide much more space for their culture. He maintains a particular interest in the ferns of South India and Sri Lanka.