Tuesday, 5 May 2009

Lords and Ladies

Lords-and-Ladies (Arum maculatum) has to be one of the strangest plants in the British Flora and also that of the Mersey Valley. It has many other vernacular names, including ‘Cuckoo Pint’ and ‘Wake Robin’, ‘Parson-in-the-Pulpit’ and ‘Bulls and Cows’. The derivations of some of these names are quite indelicate and I’ll leave you to read Geoffrey Grigson’s researches on the subject (1).

The plant has arrow-shaped leaves. The first examples that I saw, in Cambridgeshire hedgerows, had leaves with chocolate coloured spots and indeed the specific epithet, maculatum means ‘spotted’. Nevertheless, the leaves of examples in the Mersey Valley rarely exhibit spots (occasionally they may exhibit a few small flecks). Back in the 1950s Dr C.T. Prime studied this species and wrote a monograph on it (2). He found that, in England and Southern Scotland, the ratio of spotted to unspotted leaves tends to favour the unspotted variety as one moves north. This gradual change of a species character over a particular geographical area is known as a ‘cline’.

But the most striking character of Lords-and-Ladies is not the leaves but the inflorescence (the flowering part). The visible parts of this inflorescence consist of a hood or cowl shaped structure, known as a ‘spathe’, which partly enfolds a finger-like projection known as a ‘spadix’. I suppose that if you glance at this structure you might begin to understand why previous generations made up ‘rude’ names for it ... possibly (?) ... but moving swiftly on! The actual flowers are at the base of the spadix and are enclosed, and hidden from view, in a bulbous structure at the bottom of the spathe.

The strategy that this species uses to attract pollinating insects is extraordinary. It flowers in late April/early May and its pollinators are small moth flies or midges in the genus Psychoda, which lay their eggs in cattle dung. The midges fly from plant to plant, landing on the inner surfaces of the spathes. They are attracted by a ‘urinous’ smell emitted by the plants. An individual midge tends to lose its footing on the smooth surface of a spathe and to fall through a small, circular opening at its base into the enclosed ‘trap’ containing the flowers. It falls past a ring of downward pointing hairs which are, in fact, sterile male flowers. These hairs prevent the midge from exiting the trap as do a slippery layer of oil on the walls and downward-pointing wart-like projections. It then falls past the fertile male flowers and reaches the female flowers, each with a single stigma and ovary. If it has previously visited a different plant it will be covered in pollen and will pollinate the female flowers. During its imprisonment the insect feeds on sugary sap from the stigmas. After a few hours the stigmas begin to wither and the anthers on the male flowers open, showering the trapped insect below with pollen. Next, the downward pointing hairs around the exit shrivel and the surface of the spadix becomes wrinkled and rough, allowing the midge to climb to ‘freedom’. In fact, it usually flies off to another Lords-and-Ladies plant and the whole process is repeated. At any one time a trap can contain 20 or 30 pollinating insects – but as many as 4,000 have occasionally been found!

The attractive (to a midge!) ‘urinous’ smell, referred to above, is caused by the breakdown of proteins in the spadix. This also contains starch granules which are themselves broken down by certain enzymes. This chemical reaction causes the spadix to warm up, sometimes by as much as 16 degrees C above the ambient temperature. This warming effect helps to volatilise the smelly chemicals and disperse them over a wider area.

Once the female flowers are fertilised the spathe and spadix wither away and the fruits develop. These consist of a number of orange/red berries clustered at the top of a stalk. These berries contain light brown, spherical seeds and are poisonous.

Lords and Ladies is a member of a relatively large family called the Araceae. Worldwide, this family contains many members of which are even more bizarre than our Lords and Ladies - but tend to exhibit the same basic form.

Dave Bishop, May 2009


1. ‘The Englishman’s Flora’ by Geoffrey Grigson, Paladin 1975 (first pub. 1958).

2. ‘Lords and ladies’ by Cecil T. Prime, Collins 1960.

3. ‘The Biology of Flowers by Eigil Holm, Penguin 1979.

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