352 TRANSACTIOXS AND PROCEEDINGS OF THE [Sess. LXiv. 



meiitary cells ruptures the layers of cork above them, and 

 thus opens the lenticel to the atmosphere. 



The structures so formed persist apparently throughout 

 the life of the plant, and can almost, without exception, 

 even in stems of eight or nine years of age, be found at or 

 near the bases of the papilhe, to which, indeed, they are 

 confined. 



CONCLUSIONS. 



I. That in Solamon Dulcamara the adventitious roots 

 do not arise below or grow out through lenticels, as is 

 apparently the case in the majority of plants. 



II. That, as the origin of the root precedes the appear- 

 ance of phellogenetic divisions, it is entirely independent 

 of lenticellar formation. 



III. That the protuberances on the surface of the stem 

 are not lenticels, but result from the formation of a mass 

 of secondary tissue, which originates in the reaction of the 

 phellogen to the pressure set up by the elongating root 

 below it. 



IV. That the lenticels only appear after the pro- 

 tuberances are fully formed. 



LITERATURE REFERRED TO. 



1. l)e Bary. — Comp. Anut. of Phanerogams and Ferns. — English 



Edit., p. o:J.s. 



2. Beijerinck. — Beobacht. u. Betraclit. uh. Wnrzelknospen n. 



Nebenwurzeln. — Yerhand. d. Koninklijkc Akad. van Weten- 

 schappen. Amsterdam, 1887. 



3. De Candolle. — Annales des Sciences Natnrelles Bot., T. vii. p. 5. 



182G. 



4. Klebahu. — Die Rindeniioreii. .Jcnaische Zcitschrift f. Natur- 



wissen.schaft. Jena, i«84. 



;"). Klebahn. — Ueber Wurzelanlagen unter Lenticellen b. Herminiera 

 Elaphroxylon u. Solanum Dulcamara. — Flora. H. 2. 1801. 



•J. Lemaire. — Recherclies sur L'Origine et le Developpement des 

 Racines Laterales chez les Dicotyledones.— Annales des Sciences 

 Naturelles Bot., Ser. 7, T. :3., p. 224. 188(i. 



7. Stahl. — Entwickelung.sgeschichte u. Anatomic d. Lenticellen. — 



Bot. Zeit, p. oG;;. 1873. 



8. \'iin Tieghcm et Donliot. — Recherches Comparatives sur L'Origine 



des Mcmbres Endogenes. Radicelles. — Annales des Sciences 

 Naturelles Bot., Ser. 7, T. 8. 1888. 



