P.M. on the 24th it curved so rapidly down, that by 6.45 A.M. on the 25th it stood only 19o above the horizon.  It went on circumnutating in nearly the same position for two days.  Even after the flower-heads have buried themselves in the ground they continue, as will hereafter be shown, to circumnutate.  It will also be seen in the next chapter that the sub-peduncles of the separate flowers of [page 225] Trifolium repens circumnutate in a complicated course during several days.  I may add that the gynophore of Arachis hypogoea,

Fig. 92.  Trifolium subterraneum:  main flower-peduncle, illuminated from above, circumnutation traced on horizontal glass, from 8.40 A.M.  July 23rd to 10.30 P.M. 24th.

which looks exactly like a peduncle, circumnutates whilst growing vertically downwards, in order to bury the young pod in the ground.

The movements of the flowers of Cyclamen Persicum were not observed; but the peduncle, whilst the pod is forming, increases much in length, and bows itself down by a circumnutating movement.  A young peduncle of Maurandia semperflorens, 1 ½ inch in length, was carefully observed during a whole day, and it made 4 ½ narrow, vertical, irregular and short ellipses, each at an average rate of about 2 h. 25 m.  An adjoining peduncle described during the same time similar, though fewer, ellipses.* According to Sachs** the flower-stems, whilst growing,

* ‘The Movements and Habits of Climbing Plants,’ 2nd edit., 1875, p. 68.

** ‘Text-Book of Botany,’ 1875, [[page 226]] p. 766.  Linnaeus and Treviranus (according to Pfeffer, ’Die Periodischen Bewegungen,’ etc., p. 162) state that the flower-stalks of many plants occupy different positions by night and day, and we shall see in the chapter on the Sleep of Plants that this implies circumnutation. [page 226]

of many plants, for instance, those of Brassica napus, revolve or circumnutate; those of Allium porrum bend from side to side, and, if this movement had been traced on a horizontal glass, no doubt ellipses would have been formed.  Fritz Müller has described* the spontaneous revolving movements of the flower-stems of an Alisma, which he compares with those of a climbing plant.

We made no observations on the movements of the different parts of flowers.  Morren, however, has observed** in the stamens of Sparmannia and Cereus a “fremissement spontané,” which, it may be suspected, is a circumnutating movement.  The circumnutation of the gynostemium of Stylidium, as described by Gad,*** is highly remarkable, and apparently aids in the fertilisation of the flowers.  The gynostemium, whilst spontaneously moving, comes into contact with the viscid labellum, to which it adheres, until freed by the increasing tension of the parts or by being touched.]

We have now seen that the flower-stems of plants belonging to such widely different families as the Cruciferae, Oxalidae, Leguminosae, Primulaceae, Scrophularineae, Alismaceae, and Liliaceae, circumnutate; and that there are indications of this movement in many other families.  With these facts before us, bearing also in mind that the tendrils of not a few plants consist of modified peduncles, we may admit without much doubt that all growing flower-stems circumnutate.