316 Yapp . — Fruit- dispersal in A denostemma viscosum. 
interesting 1 . Cases, also in the Compositae, in which the fruit itself 
becomes mucilaginous, are described by Darwin 2 and Hildebrand 3 ; while 
a number of instances are given by various authors 4 , of plants of other 
natural orders whose fruits are said to be dispersed through the agency of 
animals, by means of glandular hairs situated on pericarp, calyx, bracts or 
other organs. But so far as I know, in none of these cases (except perhaps 
in Siegesbeckia ) is the adaptation so complete as in the one which forms the 
subject of this paper. 
In conclusion, I wish to thank Mr. Ridley, director of the Botanic 
Gardens, Singapore, and Mr. Macmillan, Curator of the Peradeniya Gardens, 
Ceylon, for kindly sending me a supply of both spirit material and ripe 
fruits of Adenostemma, , that which I had myself collected having un- 
fortunately been lost in transit. 
1 Hildebrand, loc. cit., pp. 12, 13, also Buchenau, Ueber Bltithenentwickelung bei den Com- 
positen, 1872, Bot. Zeit., vol. xxx, p. 366, with Taf. V, figs. 19-27. 
a C. Darwin, Note on the Achenia of Pumilio argyrolepis, Gard. Chron., 1861, p. 4. 
3 Hildebrand, Ueber die Verbreitungsmittel der Pflanzenfriichte durch Haftorgane, Bot. Zeit., 
1872, vol. xxx, p. 910. 
4 See Kerner and Oliver, Natural History of Plants, London, 1894, vol. ii, pp. 869, 870; also 
Hildebrand, loc. cit. (two papers), and Die Verbreitungsmittel der Pflanzen, Leipzig, 1873, pp. 88 
et seq. 
EXPLANATION OF PLATE XXIII. 
Illustrating Prof. Yapp’s paper on Fruit-dispersal in Adenostemma viscosum. 
All the figures except 7-9 refer to Adenostemma viscosum , Forst. 
Fig. 1. A flowering capitulum cut vertically through the middle. X 3. 
Fig. 2. A later stage. The involucral bracts are becoming reflexed, and the corollas, bound 
together by the hairs at their apices, are in the act of falling off in one mass, x 3. 
Fig. 3. Fruiting stage. The involucre is completely reflexed, and the fruits (only 5 of which 
remain) fully exposed. The tip of each pappus-seta is surrounded by a drop of viscid secretion, x 3. 
Fig. 4. Part of a single floret, showing the calyx-ring and two stalked glands, each with 
a pulvinus (/) at its base. Note the filamentous hairs on upper part of corolla, and the glandular 
hairs on the pericarp, pappus-setae and lower part of corolla, x 30. 
Fig. 5. Three mature glandular hairs from a pappus-seta, as seen in a longitudinal section of the 
latter. Note the density of the cell-contents of both hairs and epidermis, x 360. 
Fig. 6. Longitudinal section through the dilated base (pulvinus) of a pappus-seta, m. c. motor 
cells, cor. corolla, x 140. 
Fig. 7. Fruit of Hypochoeris radicata , before expansion of pappus,/, annular pulvinus. x 2. 
Fig. 8. Do. after expansion of pappus. Note the flattened pulvinus,/. x 2. 
Fig. 9. Tragopogon pratense. Longitudinal section through the apex of the beak of a fruit, 
showing the annular pulvinus, /. K. pappus, x 90. 
Fig. 10. Longitudinal section showing the absciss-mechanisms of the corolla and style in 
Adenostemma . N.B. The thick-walled cells are shaded, cor. corolla, n, nectary, st. style. Corolla 
ruptures at a, style at b. b. x 140. 
Fig. 11. Longitudinal section to show absciss-mechanism of fruit ; ep. thick-walled epidermis of 
base of fruit ; f funnel-shaped layer of mechanical cells connecting epidermis of torus with the vascular 
strand; t, thin- walled tissue which initiates the rupturing process, x 100. 
