FOUR single genus plant books have caught my eye. Iris by Theodore James junior, sprouts the claim that these plants are second only in popularity to the rose (Abrams £12.95). I like them and would agree that they are not fussy, bloom if "benignly neglected" and are not much troubled by pests and diseases. And of course they are vivid and architectural.

The Egyptians took to them in 7000 BC, the Romans used the root to freshen their breath and the medieval French adopted them as the their national plant (fleur de lis). The Germans put the root (orrisroot) in beer, the French in wine. Native Americans used iris leaf fibres for rope, Japanese ladies used it for whitening their faces, but all this pales beside the beauty of the plants.

From the same author, the same publishers and at the same price is Tulip. The Turks first championed them but it was the Dutch who suffered famously from "tulip mania". Lovers of seventeenth century Dutch painting can select the contemporary streaky coloured Rembrandt types, dealers in stocks and shares could also grow these or the chrome-yellow Tarda species to remind themselves of the dangers of speculation, as it was the collapse of "tulip futures" (gambling what the bulb would bring) that nearly brought down the Dutch economy in 1637.

Farmers diversifying into biomass willows are also troubled. But generally, and as I read in Willows: the Genus Salix by Christopher Newsholme, the trees "appeal to others who like me are past their prime and require quick results from their labours" (Batsford £17.99).

The author plants out the pre-history, the willow as one of the earliest pre-Ice Age flowering plants, dominant 70m-135m years ago, and its long association with its main pollinator, the honey bee, which insect has been dated in amber to 90m years ago.

Following this the history, with mention of Queen Boadicea's coracles, Salix triandra for basket making (the best rods from the female trees), cricket bat willows (the bats from female trees) and for decorative garden planting (the males are the loveliest). They provide food for Australian horses, rabbits don't like the very bitter Salix purpurea, ethnic medicines use the willow's aspirin effect, and roadside planting for noise and pollution barriers looks set to spread here from Holland.

Christopher Newsholme holds the national collection of willows and provides a botanical analysis of the numerous varieties, from the big trees to tiny creepers for the rock garden.

Lastly there is Cyclamen by Christopher Grey-Wilson (Batsford £30). I was pleased to get this so as to identify one that a friend gave me a few years ago. This was simple as there are only 22 species, and I learnt that my C balearicum's endearing habit of flowering before it leaves up is a function of the way I treat it; perhaps it has had a regime of over-harsh summer drying out.

They are Mediterranean plants so need a summer rest, and in fact are quite tricky things as anyone will know who has bought and killed a sequence of them from the florists. Grey-Wilson describes the veg shop type of cyclamen as "blowsy and over endowed with blossom". Better the others - get it right and the reward is flowers in the house or garden nearly all through the year.

All the above are well-travelled plants, and to reinforce the fact that we got many of them from far away gardeners, I would suggest a dig into Earthly Paradises: Ancient Gardens in History and Archaeology by Maureen Carroll (British Museum Press £14.99).

Consider happier times in the "Axis of Evil". A beautiful painting shows a part of a Baghdad palace garden in AD 1396. The royal gardens of Persia were copied in Europe in the Middle Ages. To quote from an ancient Egyptian verse:

The hot-headed man in the temple

Is like a tree grown in a garden

The truly temperate man sets himself apart,

He is like a tree grown in a sunlit field.