126 



PRINCIPLES OF PLANT-TERATOLOGY. 



BIBLIOGRAPHY. 



Berg. — Einige Spielarfcen der Fichte." Sitzb. Naturf . Ges. 



Dorpat, Bd. viii, 1 (1886), pp. 157-163. 

 Carriere. — Traite general e des Coniferes, pp. 330-331. 

 Paris, 1867. 



Caspary. — "Zwei Schlangentanneu (Abies pectinata D. C. f. 



virgata Caspary)." Bot. Zeit., Jahrg. xl (1882), p. 778. 

 Dutch art re. — "Note sur an fait de vegetation du Lilium Neilg- 



herrense: 3 Bull. Soc. bot. Fr., vol. xxiv (1877), p. 183. 

 Goebel. — Organography of Plants, vol. ii, p. 463. Oxford, 1905. 

 Einleitung in die Experimentell-Morphologie der 



Pflanzen. 1908. 

 Klebs. — Willkiirliche Entwickelungsanderungen bei Pflanzen, 



etc., pp. 48, 84, 87. Jena, 1903. 

 Thomas. Fr. — "Picea excelsa Lk. lusus cujpressina" Mitt. 



Dendrol. Ges., Bd. xvi (1907), p. 252. 

 Yochting. — " Uber die Regeneration der Araucaria excelsa " 



Pringsh. Jahrb., Bd. xlix (1904), p. 144. 



4. ADVENTITIOUS SHOOTS. 



Adventitious organs are those which arise at a later 

 period than their usual time of origin, out of their 

 normal position, and in what one would regard from 

 the a priori standpoint as unexpected places. And this 

 is a correct way of envisaging the phenomenon, for, 

 phylogenetically, the three essential organs, shoot, root, 

 and leaf, have a definite mutual relation and origin 

 which are maintained in all ordinary circumstances ; 

 but here and there specific changes in the environment 

 and in the constitution of the individual have led to the 

 abnormal production of certain organs which we call 

 "adventitious." Adventitious shoots are exceedingly 

 common and of many kinds. They may be classified 

 according to the organs on which they occur. A shoot 

 is produced normally from another shoot as a branch 

 in the axil of a foliar organ. This shoot, however, is 

 not always strictly in the axil, but sometimes occurs 

 either on the leaf-base or on the main axis a short way 

 above the leaf -insertion. Following Celakovsky in 

 regarding so-called "axillary" shoots as always occur- 

 ring on the leaf, it is evident that they represent normal 



