A NOVEL PLANT OF GREATER STITCHWORT
PRODUCING PETAL-LESS FLOWERS

In the late spring of 2002 I discovered a very unusual plant of greater stitchwort Stellaria holostea.  It was in full bloom but none of its flowers had any petals. Normal plants bear flowers with five notched petals some 10 mm long.  The apetalous plant was located by a track between Depden and Chevington in West Suffolk (TL778583).  It was highly vigorous and its morphology appeared to be identical to that of normal plants, except for the lack of petals (see photographs, centre pages). 

S. holostea is abundant in this area of heavy clay but this was the only apetalous plant found over a three-year period.  The apetalous trait must therefore be only rarely or perhaps never passed on to progeny.  The same apetalous plant was also observed in the 2003, 2004 and 2005 seasons.  As in 2002, none of the flowers bore petals, yet the plant was growing well and was successfully competing for space with other plants.  In 2004 the mature fruits of the apetalous plant were examined and were shown to contain some seeds, though their size was variable, ranging from normal size to a third the usual diameter.  

Brenan & Lousley (1944) briefly described a petal-less variant of greater stitichwort.They listed four reports of individual plants being found in Hereford (1848), Somerset (1896), Surrey (1902) and Worcestershire in 1908.  No modern references have been found for apetalous flowers for this species.

It is intriguing why my very vigorous, apetalous plant appears not able to pass on its unusual trait. Presumably it arose in the first place as a result of a spontaneous mutation, as it is so rare. Perhaps the plant is not able to produce any seed by self-pollination (which would be expected to grow into apetalous plants).  Greater stitchwort normally produces seed through cross-pollination, aided by small bees, and various flies and beetles. A cross between the apetalous plant and a normal plant would probably produce plants with flowers bearing petals.

If anyone has observed the apetalous trait in this species I would be very interested to know.

I am very grateful to Peter Benoist, the BSPB Specialist on Stellaria for providing the reference.

Brenan, J.P.M. & Lousley, O.E. 1944.  Floral Variations in Stellaria holostea, Botanical Exchange Club Report  840-846.

peter.i.payne@depden- green.freeserve.co.uk