Category Archives: Nemacianthus

Mayfly Mystery

The Mayfly Orchid is a small orchid with very dark reddish brown flowers with long, hair-like sepals.  It flowers from late July to August.  One might question what sort of insect was behind the naming of this orchid, which does not even flower in May.  Mayflies are an insect with which many of us are not acquainted.

Nemacianthus caudatus

Close view of a typical flowering Mayfly Orchid

One source attributed the naming or the orchid being similar to the long legs of a Mayfly.  However, a quick search in the Internet revealed that Mayflies have fairly short legs, as in the image below:

It turns out that it is the appendages on the end of the abdomen that the sepals of the Mayfly Orchid resemble.  Mayflies usually have three tails (two cerci, one middle filament), although the middle tail is rarely reduced or absent.  All the tails are longer than the body, thread-like and similar in size.  Thus the three tails correspond with the three long sepals of the Mayfly Orchid flowers.

This is only half of the story; mayflies occur in swarms and these resemble colonies of Mayfly Orchids.

Nemacianthus caudatus

A colony of Mayfly Orchids in the Adelaide hills

Mayflies are a sign of summer in parts of the United States of America Source: http://www.severnsound.ca/SSEA_Mayflies.htm

Adult Mayflies are short-lived.  Most live for one or two days, but some for only a few minutes.  They form mating swarms.  Some swarms are quite impressive, even on Doppler weather radar.

So you may want to keep a lookout for colonies of Mayfly Orchids in August and see if you can imagine a swarm of insects with three long tails on their abdomens.

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The Mayfly

Nemacianthus caudatus – Mayfly Orchid

Acianthus pusillusThis little orchid is very similar to Acianthus pusillus but flowers in spring instead of autumn.  It has similar heart-shaped leaves to Acianthus pusillus, but the flowers are very differentThey are often found growing together.

The Mayfly orchid has graceful long sepals compared to a relatively small flower.  The whole flower stalk is a dark red, which makes it a challenging subject to photograph in low light.

It is often found growing at the base of tress in the leaf litter, in small colonies.  The flowers attracts its pollinator, a small gnat, by giving off a musty odour which we can also detect.  Once pollinated, the ovaries (pictured left) swell with many tiny seeds within.

Nemacianthus caudatus.docx

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