13 



INTRODUCTION. 



To this type belong the maiority of the Dicotyledons. Helianthus annuus, Fago- 

 pyrum, Raphanus sativus, IMyiinjihyllum, species of Salix, Casuarina stricta, Linum 

 usitatissimum, and Primulacene ^ l:ave been carefully investigated. 



4. The fourth Angiospermous type (Fig. 5) is observed in those of the 

 Cucurbitaceje (Cucurbita) and Papilionaceaj (Pisum, Phaseolus, Cicer) which have 

 been investigated. Here a common initial zone extends transversely over the 

 puncium vegeiationis \ by the divii^ions in this arise, on the side towards the 



FIG. S- — (210) Pisum sativum. Median longitudinal section through the apex of the root, after Janczewski. /— / iileronie, 

 p — r periblein, ^common transverse initial zone, c its lateral continuation, 



root-cap, successive layers, which are added to the conical middle portion of the 

 latter. On the side of it facing the body of the root arise a massive plerome-cylinder, 

 and a periblem many layers of ct'ls thick, having approximately the form of a hollow 

 cylinder open towards the initial layer. From its margin the transverse initial zone 

 of meristem curves itself round, so to speak, over the adjoining outer surface of 

 the periblem, and acts here for a further space as initial layer, on the one hand 



* Kamienski, Zur vergl. Anatomic d. Primeln, Strassburg, 1875. 



