Oxalis acetosella L., small morph (Finland, Tampere, Viitapohja 1991;
on the right) and typical morph (Finland, Lammi, Biological Station, 1991; two
plants on the left).
– Image: Harri
Harmaja (scanned from dried specimens).
– The small morph differs
from typical O. acetosella (Oxalidaceae): (i) the plant is smaller
in all parts, (ii) the rhizome is usually short, erect and unbranched,
with a prominent primary root, developing relatively short branches in age, (iii)
the leaves are generally more
numerous at the rhizome tip, thus often forming a true rosette, (iv) the
leaves are darker green above, (v) the underside of the leaves has
usually more anthocyanin pigment in the spring, and (vi) the lower surface
(between the midribs and the margins) of the terminal leaflet is hairless as are
the surfaces of the distal halves of the adjacent basal leaflets (vs. more or
less hairy everywhere in typical O. acetosella). A few intermediate appearing plants have also been
noted.
I have observed this morph only in a few places in southern
Finland. Usually it was found in a niche other than "typical" forest ground: in
pathsides, by boulders, near bases of spruce trees, by trunks, and in rock
terraces, often in somewhat sheltered places partly under twigs and leaves.
The small morph has generally chasmogamous and probably also
cleistogamous flowers. Some plants are clearly seedlings
with green cotyledons still attached, having developed from the seed bank in the preceding season, others are somewhat older.
The morph does not appear merely to represent seedlings of typical O.
acetosella as the latter have been noted and they are different. The
difference between the morphs in the underside indumentum of the leaflet halves
is most interesting. Its constancy should be checked with additional materials.
The small morph may, despite of all features presented above, be some curious
juvenile stage of O. acetosella, or it may represent a separate taxon. The old, neglected name O. parviflora Lej.
is apparently based on some small-flowered O. acetosella plant from
Europe, but it does not seem to refer to the present morph.
Created August 26, 2004.