Room 10, of Balclutha Primary School, asks :-

Jenny Harris, of Balclutha Primary School, asked:-

What type of clover has these red spot marks? I have never seen this type before and we walk the dog a lot and in a variety of places. We find heaps of 4 leaf clovers and we look for them but not this clover with the red makings. It is growing at our school of all places.

Sue Gibb, of the Allan Herbarium at Landcare Research, responded.

White clover is known for having a number of visible polymorphisms (literally many forms). These include the 4 leaved form, the ability to produce cyanide when tissue is damaged, and a number of leaf mark patterns. Red leaf mark patterns include red flecking, red midrib, red V-mark, and red spots.

Just as in humans where there are different eye colours that are inherited traits, so leaf markings (or absence thereof) are inherited traits in clover plants.

The red markings contain coloured chemicals called anthocyanin pigments. It has been found that many of the markings that contain anthocyanin are best observed at temperatures below 10°C. Some of the traits are not visible in summer, although I do not know if this applies to the leaf spot trait.

You will know that a chemical called DNA (deoxyribonucleic acid) that is passed on from parent to child in living creatures has the key to inherited characteristics. DNA is found within cells as chromosomes (46 in humans, and 32 in white clover). A baby gets 23 chromosomes from its father and 23 from its mother. Similarly, each white clover seed gets 16 chromosomes from each of its parents. Where the chromosomes from mother and father differ in the information they carry, what their child looks like depends on the interaction of the information on the chromosome.

In humans we have traditionally said that if you get information for blue eyes from one parent and for brown eyes from the other parent, then you will get brown eyes. If you get information for brown eyes from each parent then you will get brown eyes. However, if you get information from both parents for blue eyes, then you will get blue eyes. We say that blue eyes is a recessive condition because you need two sets of information to have the condition “expressed”.

In clover it gets more complicated, as the chromosome number has doubled at some stage in the history of white clover, so instead of one set of chromosomes from each parent, a clover seed gets 2 “sets” of 8 chromosomes from each parent plant. With four sets of chromosomes all interacting, the genetics is a bit more complicated too.

Your red spot polymorphism occurs occasionally.There are several several clover red mark shapes possible, other than dots, some are like arrowheads and some are like fern leaves.