Lavatera No More

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Lavatera × clementii ‘Rosea’ is now Malva × clementii ‘Rosea’. Photo: gardenersdream.co.uk

Yes, the genus Lavatera is gone, taxonomically speaking at least, and its species have been transferred to Malva, commonly called mallow. Genetic and morphological studies published in 1998 by botanist Martin Forbes Ray show that the two genera showed so many common characteristics there was no reason to separate them. 

The combined genus now contains some 50 species, including annuals, biennials, perennials and soft-wooded shrubs.

A Gardener’s Reaction

Malva moschata (left), the former Lavatera thuringiaca (right). Not much of a difference, is there? At least, not in the flowers. Photo: plants.alsipnursery.com & Nordelch, Wikimedia Commons

In a sense, this will be a relief to gardeners like me who’ve always had a hard time telling lavateras (Lavatera spp.) from mallows (Malva spp.). In fact, most of us have always called Lavatera species mallows anyway, or possibly tree mallows if we were trying to make a distinction between the two. 

However, Linnaeus, who originally separated Lavatera from Malva, was big on floral parts as a means of identifying plants and came up with the following means of distinguishing between the two: in Lavatera, the epicalyces (an additional row of floral parts below the sepals) are fused together at their base, while in Malva they’re free (not fused together), although they may be fused to the sepals. What? I mean, did you even understand that? At best, you’d have to turn the flower over to distinguish the two. 

Today, though, DNA is considered more valuable than flower bits, resulting in many changes in horticultural nomenclature … as with incorporating Lavatera species into the genus Malva.

Denial or Acceptance?

But I’ll have to change my plant labels! Ill.: Chelsea O’Byrne, http://www.theglobeandmail.com

This name change is only being very reluctantly applied in the horticultural world (nursery people generally don’t like it when plant names change!), so most sources either still use Lavatera alone, while others still list Lavatera, but mention the genus change in their plant descriptions. Even Wikipedia has only recently started to acknowledge it. The statement “All species previously placed in Lavatera have now been transferred to the related genus Malva” now appears on the Wikipedia Lavatera page with a similar mention on the Malva page. But there is still a Lavatera page.

For most species, only the genus name changes, so, for example Lavatera thuringiaca simply becomes Malva thuringiaca, so there really isn’t much to remember. Especially since the average gardener has always called lavateras by the name mallow anyway.

The annual mallow, formerly Lavatera trimestris, is now Malva trimestris. Photo: http://www.vanmeuwen.com

Here some of the better-known species with their new names:

  • Malva cachemeriana (formerly Lavatera cachemeriana).
  • Malva × clementii (formerly Lavatera × clementii).
  • Malva maritima (formerly Lavatera maritima).
  • Malva olbia (formerly Lavatera olbia).
  • Malva thuringiaca (formerly Lavatera thuringiaca).
  • Malva trimestris (formerly Lavatera trimestris).

So, change your labels … or don’t. But I think the gardening world will slowly come to accept this change. It’s such an obvious one!