Dr. Judy Rose
is a retired research scientist. She is trying to establish a national collection
of Jasmine with both pin and thrum plants of as many species as possible.
Particularly keen to find thrum plants of J. azoricum, J. mesnyi, J. nudiflorum
and would be interested to hear from anyone willing to exchange cuttings or
seeds of Jasminum species.
Dr Judy Rose (UK)
"...Most Jasmine plants are self-incompatible, the pollen cannot
fertilise the ovules. The incompatibility in Jasminum is similar to that
in Primula, which is known to many people. The plants come in two morphs
or forms. In one in form, the style is longer than the stamens, these
are called "pin" or long-styled flowers. In Primula, the style
and stigma (the receptive surface on the end) looks just like a pin. In
Jasminum the shape of the stigma varies with the species and often does
not look much like a pin. In the other form, the stamens are situated
at the mouth of the corolla tube above the style, these are called "thrum"
or short-styled flowers. Thrum is an old weaving term meaning that the
threads pass over the top. In order to get seed set the pollen from a
pin plant must fertilise the ovule of a thrum plant or vice versa. Below
are pictures of a section of both a pin and a thrum flower of J. beesianum
with the flower parts named for those not familiar with them..."