15. HANSTEIN, J. Ueber die Organe der Harz- u. Schleim-Absonderung in den Laubknospen. Bot. Zeit. xxvi. 697, &c. (1868).

16. TREUB, M. Jets over Knopbedekking in de Tropen. Handel. 1st. Nederl. Natuur- en Geneeskund. Congr. 1887,130. Abstract in Botan. Centralbl. xxxv. 328 (1888).

17. OHLERT, E. Einige Bemerkungen über die Knospen unserer Bäume und Sträucher. Linnæa, xi. 632 (1837).

18. HENRY, A. Knospenbilder: ein Beiträg zur Kenntniss d. LaubNova Acta Acad. Caes.-Leop., xxii. 171 (1847). Recherches sur les Stipules. Ann. Sci. Nat.

knospen.

19. COLOMB, G.

(ser. 7), vi. 1 (1887).

20. BENTHAM, G.

Revision of the Mimoseæ. Trans. Linn. Soc.

xxx. 341 (1875).

21. BELT, T. The Naturalist in Nicaragua, 218 (1874).

22. BOWER, F. O. Proc. Phil. Soc. Glasgow, xviii. 320 (1887). 23. SCHUMANN, K. in ENGLER and PRANTL, Pflanzenfamilien, iv.

pt. 4, 12 (1891).

24. TYLER, A. A. The Nature and Origin of Stipules. Annals New York Acad. Sci., x.

25. REINCKE, FR. Ueber die Knospenlage der Laubblätter bei den Compositen, &c. Inaug. Dissert. Heidelberg, 1893.

26. GREVILLIUS, A. Ueber die Stipelscheide einiger PolygonumArten. Botan. Centralbl. xxx. 254, &c. (1887)

27. VINES, S. H. Students' Text-book of Botany, 45 (1894). 28. NORMAN, J. Quelques Observations de Morphologie générale. Ann. Sci. Nat. (ser. 4) ix. 135 (1858).

29. STENZEL, G. Ueber Nebenblattbildungen.

Gesell. Vaterl. Cult. (Breslau) lx. 224 (1882).

Jahresb. Schles.

30. CAUVET, D. Probabilité de la présence des Stipules dans quelques Monocotylédones. Bull. Soc. Bot. France, xii. 241 (1865).

31. VAN TIEGHEM, PH. Traité de Botanique, 318 (1884).

32. BAILLON, H. Recherches sur l'organisation &c., des Caprifoliacées. Adansonia, i. 372 (1861).

33. GRAY, A. Structural Botany, 435 (1879).

34. BENTHAM, G.

Handbook of the British Flora, 9 (1858).

35. LINDLEY, J. Introduction to Botany, 99 (1832).

36. AGARDH, J. G. Om Växternas Stipler. K. Vetensch. Akad.

Handb. 1849, 37 (1851).

37. CLOS, D. Indépendance, développement, anomalies des Stipules. Bull. Soc. Bot. France, xxvi. 189 (1879).

38.

Des Stipules et leur rôle dans l'Inflorescence et dans la Fleur. Mém. Acad. Sci. Toulouse (ser. 7), x. 201 (1878). 39. TURPIN, P. J. F. Essai d'une Iconographie des Végétaux, 1820. 40. KRONFELD, M. Ueber die Beziehung der Nebenblätter zu ihren Hauptblättern. Verhandl. Zool.-Bot. Gesell. Wien. xxxvii. Abhandl. 69 (1887).

41. For further Information and Literature of the subject of Leaffall, see RENDLE, A. B., 'Natural Science,' i. 680 (1892).

Detailed accounts of observations on the stipules of many genera and species, arranged under their families, will be found in the following papers :

LUBBOCK, Sir J. On Stipules, their Form and Function. Journ. Linn. Soc. (Bot.) xxviii. 255 (1890), xxx. 463 (1894), and xxxiii. 202 (1897).

Were I a skilful painter,

What should I paint for thee? A tiny spring bud peeping out From a withered wintry tree.

G. MACDONAald.

EVERYONE who loves a garden knows to his cost how susceptible young leaves are to cold-how often the bright promise of spring is ruined by late frosts. Buds offer also a tempting food to insects and other animals. Moreover, their development is generally a slow process, the buds for the following year being already formed, as a rule, during the previous summer, in many cases as early as June or July, and in some even a year and a half in advance. The protection of the buds is therefore one of the most important requisites in plant lite-in cold countries against frost, in hot against the sun. During winter the young leaves lie snugly enclosed in several warm wraps, covered in many cases by furry hairs, and often still further protected from insects and browsing quadrupeds by gummy or resinous secretions.

The bud is a short shoot bearing a number of young leaves closely packed together. There is generally one

B

at the summit of each twig and in the axil of each leaf.

When the year is divided into favourable and unfavourable seasons, marked either by alternations of temperature or by drought and rain, there is often a marked difference between 'growing' and 'resting' buds. Moreover, among our own species there is often a considerable difference between terminal and axillary buds, as, for instance, in the Black Poplar (Populus nigra).

FIG. 1.-YOUNG SHOOT OF TULIP TREE (Liriodendron), 1 nat. size.

The following figure (fig. 1), representing a young shoot of a Tulip Tree, is an illustration of the necessity for such protection. It will be seen that the outer (lower) leaf, which had only a single covering, has been killed by frost, while the succeeding one, which had two wraps, has escaped.

It is remarkable that some

nearly allied genera, and even in certain cases species of the same genus, often differ in the method of the protection of the bud. This is the case, for instance, in the Willows and Poplars, the function being performed in the Poplars by stipules, in the Willows (though they possess stipules) by leaves.