Tuesday, 11 September 2012

Wednesday wildflower: miner's lettuce

Claytonia perfoliata, basal leaves

Miner's lettuce, Claytonia perfoliata, is wild foragers' fare.  Its succulent leaves can be lightly steamed or eaten fresh in a salad.  The plants are annual, and I first noticed the seedlings about 6 weeks ago.  Lately there have been a few early flowers.

The little white flowers form in clusters in the centre of roughly circular bracts.  Each flower has two sepals, five petals, five stamens, and three stigmas on top of the ovary.  The flower stalks elongate as the flowers get older.  The seeds are small, shiny, and black.
Claytonia perfoliata.  Basal leaves, A, adaxial, B. abaxial; C. perfoliate bract with flowers; D inflorescence and side view of flowers, showing the paired sepals.

The genetic revolution in classification has affected few plants more than it's affected miner's lettuce and its relatives.  It used to be classified with Portulaca in the Portulacaceae.  It was a big surprise to discover that the cactus family arose within that lineage, and this brought about the suggestion that the two families should be combined.  However, more recently, an alternative has been proposed: the Portulacaceae can be broken up into a number of smaller families that can sit alongside Cactaceae.  One of these is the now very much smaller version of Portulacaceae (New Zealand has a couple of naturalised species of Portulaca), but miner's lettuce and some other naturalised and native New Zealand plants ended up in the Montiaceae.  I'll certainly cover Calandrinia menziesii and Montia fontana as future Wednesday Wildflowers if I get suitable material, but for now here are some native species in Montiaceae.
Montia australasica, a common and variable alpine species found in New Zealand and Australia, at Rastus Burn, Remarkables Range, Otago.  Some botanists prefer to divide it into at least 7 species.
Montia fontana subsp. fontana is a native aquatic, here growing in a stream at Sandy Bay, Enderby Island.  M. fontana subsp. chondrosperma seems introduced, and grows on soil.

Hectorella caespitosa, here at Rastus Burn, Remarkables Range, Otago, used to be classified with its close relative Lyallia kerguelenensis (from Kerguelen Island) in its own family, Hectorellaceae.  Now their relationships are better known, they're placed in Montiaceae.  Some argue the two should be in the same genus (Lyallia caespitosa would then be the name for our species).

1 comment:

  1. Hi Phil, been out of the country - but I thought Claytonia (Montia?) australasica had been split by Heenan into several species? The plant you picture is one that I was identifying as Neopaxia sessiliflora under the old name - now M. sessiliflora. Illustrates your point about the taxonomic chages in the group, and that it extends to species level