Arums
What are they?
The arum family is a highly variable family in the appearance of its members, especially in the tropics where there are many species of vines and scrambling species that are also popular as house plants. However, in our more temperate climate, this family consists of a small number of herbaceous species, with a mix of both native and introduced species being present in our region.
Where are they found?
Generally speaking, arums largely favour damp soils and most are species of wetlands or of heavier, moist soils in woodland habitats. Species that occur as garden throw-outs may, of course, be found surviving for a time anywhere that garden waste gets dumped.
Identification
There is much variation in leaf shape and markings in this family, but the flowers are amongst the most distinctive of all plant families and immediately identify tham as arums. The petalless flowers are densely packed on a very complex structure, typically consisting of a narrow, finger-like spike called a spadix that is surrounded by a hooded, leaf-like sheath called a spathe. The spathe may be absent or reduced in some species. In the Arum species, the male flowers appear in a narrow cluster above the female flowers (see left hand picture at the top of this page which shows an opened spathe, exposing the purple male anthers above the cream-coloured female stigmas) at the base of the spadix. On other species such as the skunk-cabbages, the densely packed flowers are carried on the full length of the spadix, with the female parts of the flower maturing ahead of the male parts (the two central pictures above show skunk-cabbage flowers with female parts mature (left) and male parts mature (right)).
Identifying the species is relatively straightforward, using a combination of leaf characters and flower shape and colour. The fruits are a spike of berries, but many of the introduced species favour warmer climes and don't fruit regularly in the UK.
Common Lords-and-ladies Arum maculatum
(Cuckoo Pint, Wild Arum) Native. Found in shady places throughout much of the region, though rare in the driest soils of Breckland and The Sandlings as well as in the open habitats of The Fens and Broadland. Flowers April to May. Leaves appear in spring, more or less with the flower. The leaves are highly variable in shape, though typically somewhat arrowhead-shaped, while the leaves may be all green or have blackish spots. In the flower structure, the upper part of the spadix is usually dark maroon in colour, but may occasionally be creamy or yellow. The spadix is typically about a third the length of the spathe.
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Italian Lords-and-ladies Arum italicum
Introduced in our region, but native in southwest Britain. Cultivated forms are popular garden plants and may sometimes be found on shady roadside banks near human habitation or in churchyards. Flowers April to May. Leaves appear in autumn and form good-sized clumps through the winter. The leaves of the native subspecies neglectum in southwestern Britain are green with slightly paler veins but this subspecies probably doesn't occur in our region. Cultivated forms of subspecies italicum with highly ornamental leaves that have white or creamy markings on them are occasionally found as garden escapes. In the flower structure, the upper part of the spadix is cream-coloured or yellow. The spadix is typically about a half the length of the spathe.
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Altar-lily Zantedeschia aethiopica
Introduced from Africa as an ornamental garden plant and not fully hardy in the UK, but milder winters may see it surviving for longer where dumped with garden waste. Flowers typically August to October. Leaves typically larger and longer stalked than those of our native Common Lords-and-ladies.
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Yellow Skunk-cabbage Lysichiton americanus
Introduced as a garden ornamental from western North America. Favours very wet ground and is grown in a few local plant collections. A potentially very invasive species in wetland habitats and already showing signs of spreading rapidly on the very edge of the Broadlands region. Flowers March to April. The name comes from the foetid smell of the mature flowers which attract flies for pollination. Leaves expand greatly like rhubarb after flowering is over.
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Dragon Arum Dracunculus vulgaris
Introdcued from southern Europe as a garden curiosity but not fully hardy in the UK and recorded only as a casual throw-out from garden waste in Suffolk. Flowers May to July. A remarkable plant when seen in all its glory, with leaves to 180cm high and flowers with spathe to 50cm in length, but the foetid smell can be an acquired tatse!! This is just one of several species sometimes sold in horticulture as Voodoo Lilies.
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