Captivating Catasetinae

In January I was lucky enough to attend a talk by Max Hopkinson on his Catasetum collection, at a meeting of our East Midlands Group.

The Catasetinae tribe or sub-tribe represents a secondary rank of taxa coming between Family(Orchidaceae) and genus (Catasetum, Clowesia, Mormodes, Dressleria & Cycnoches). They come from Central and South America, as far south as the border of Argentina, and when Max started collecting, they were not well known in the UK.

Initial attempts to find how many there were turned up approximately 25 in the popular orchid ‘bibles’ of the time. When he wrote to Kew for a list he was sent one of 193 Catasetum alone! Once the list had been checked and adjusted for synonyms it totalled 130 species.

Before the internet became such a useful resource for plant identification Max was asked to send flowers preserved in spirit to Kew for identification; as he had no spirit he put them in a bottle of gin. Kew replied a year later saying they had been unable to recognise the flowers; there is no record of what happened to the gin.

Catasetum are different to many orchids; they are mainly deciduous between November and March; but for the first time in 2011/12 have not gone into dormancy . In the cold of last winter 50% of plants were lost, and the remainder were late to start growing. They were still actively growing on 14th Jan 2012. Max said he was going to try and get them through the full season and to dormancy in  November 2012.

They have male, female and hermaphrodite flowers. The females are green hooded and ugly, and pretty similar from species to species.  The plants will only produce female flowers if they are grown in high light levels; but if they are too high they will only produce females not males. The flowers can be all female, mixed on a spray or one spray of each.

The pollen is fired outwards and designed to stick on the back of Euglossine bees. The flower spike unusually arises from the base of the pseudobulb. Some flowers have a light smell, some smell of germolene. They are prone to lots of  pests and diseases! Mealy bug, scale insect, aphids, slugs and snails, mice and rats.

Max grows his Catasetum in 50% sphagnum moss, 25% bark and 25% foam; though it is  difficult to get hold of foam without fire retardant now, which is not good for them. They are watered with rainwater and fed well when growing, with a higher nitrogen feed than used for most orchids.

They need a temperature of 16ºc minimum which can be difficult to maintain in a harsh winter. The Barbara Everard trust kindly gave £500 to replace some of the plants lost in the last winter, which has enabled Max to rebuild the Collection.

The above is just a small amount of the information that Max gave during his talk, which was absolutely riveting.

Photos courtesy of Jack Lamb.

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About mercym

Plant Conservation Officer for Plant Heritage
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