A Mutant Speciman of Digitalis Purpureum...

This is a photo of one of my favorite northwest weeds, Digitalis Purpureum. It is commonly known as foxglove, but is also called "fairy bell", fingerflower, and fingerroot. The bell-shaped flowers entice curious gardeners to insert their fingers! Hence the Latin name as well as the common names all make referenceto fingers. Foxglove is a native of Europe, but is found in North America west of the Cascade Mountains from central California to British Columbia. The heart stimulant digitalis is derived from this species, making it deadlytoxic to unsuspecting small children and grazing animals.

This unusual mutant specimen was discovered in my garden in the spring of1997. Normally the bell-shaped flowers on the stem continue to the top and gradually become smaller and smaller causing the stem to terminate in a point. This specimen developed a large, relatively flat terminal flower with multiple petals.

I e-mailed this photo to Dr. Dick Olmstead at the University of Washington.He wrote back, "I'm sure it is the result of what is called a homeotic mutant, one that affects a gene that regulates flower development. In fact, I think there is one described for snapdragons that results in a radially symmetric flower at the tip of the inflorescence (actually the whole inflorescence is made to be determinate and the flower is at its tip), rather than the typical condition in which the stem continues to grow and produce flowers laterally, which are bilaterally symmetric." Inflorescence refersto a floral axis with its appendages, or to the mode of development and arrangementof flowers on an axis.

Later Dr. Olmstead found the following reference, "Thisphenomenon is called terminal peloria because only the terminal flower is affected, in contrast to general peloria, which affects all flowers on the inflorescence. The inheritance of terminal peloria has been studied in Antirrhinum (snapdragon) and shown to be caused by a single recessive allele at a locus called 'centroradialis'. Similarly, a single recessive allele can confer terminal peloria in Digitalis Purpurea (reference cited dates to 1910), a member of the same taxonomic family as Antirrhinum.In the case of Digitalis the large terminal flowers can have as many as 19 petals, 15 stamens, and a proliferation of central carpels."

He also wrote that, "because this is a recessive gene, if you want to grow these in future years you will have to self pollinate the flowers and collect the self fertilized seed for future plantings."