The photograph below shows the flowers of Campanula persicifolia. Label structures I, II and III.

Using the external features shown in the photograph, state the phylum to which this plant belongs.

Comment on the hypothesis that the plant shown in the photograph could be pollinated by an animal.

Outline the use of the binomial system of nomenclature in Campanula persicifolia.

I. sepal;

II. ovary / receptacle;

III. petal;

Angiospermophyta / Angiospermophytes / Angiosperms

Do not accept flowering plants.

a. confirms the hypothesis;

b. stigma/anther inside the flower/ring of petals so as visiting animal enters it brushes past them;

c. colourful petals (provide contrast) so that flowers can be seen by animals;

d. (slightly) cone-shaped flowers so animals come in;

a. first name/Campanula for genus / second name/persicifolia for species;

b. (all) members of Campanula persicifolia share special/unique features;

c. two names make a unique combination to designate species / worldwide recognized nomenclature;

Of all the comments received from the G2 forms, question 2 received by far the most. Most said that the photograph was difficult to interpret. If it had been in colour then it would have been far easier. However, as none of the candidates would have seen it in a book, it was fair for everyone.

A surprising number of candidates failed to gain any marks at all, not managing to identify I as the sepal, II as the ovary or receptacle and III as the petal. At the other end of the scale there were several centres whose candidates gained full marks. It seems that the teaching of Topic 9, Plant Science is very varied.

About half of the candidates correctly stated that the plant was an angiosperm, with most of the other half saying that the phylum was dicotyledons.

Most stated that the violet petals would attract animals/insects, but did not “comment on the hypothesis” as instructed. Many mentioned nectaries which could not be seen in the photograph. Few stated that the stigma was inside the flower (not evident from the central two flowers, but evident from the one shown in profile), so the pollen could be rubbed off as the animal entered. A surprising number replied that it was not due to animals, but due to insects.

Only about half of candidates were able to gain the mark for stating genus for Campanula and species for persiciflora. Fewer gained a second mark for saying that all members of C. persiciflora share unique features or that is a worldwide nomenclature.