14 CAMBIUM AND MERISTEM. 
All tissue capable of multiplying by division was described by 
Schleiden, Schacht, and others as cambium. Naegeli* perceived that 
re a mar istincti i 
young fibro-vascular bundle and the cambium of Sanio, giving to the 
former the name procambium. 
mbium, then, is the tissue of the young fibro-vascular bundle 
before it becomes differentiated into the various forms of permanent 
tissue. Cambium, on the other hand, is that zone of tissue between the 
xylem and phloem part f the LL vase 1 1 VW f 34: Psi, es. | —— 
chi(—gymno) sperms on wl ich the ci ferent 
in rows, and from the periblem the cortical tissues develope, 
i ith. The 
pericambium, which is a single layer of cells, exists only in roots, and 
separates the periblem from the plerom—being, in fact, the external 
layer of the plero: 
hi 
with its appendages, we may consider as dermatogen tissues—a ve 
* Beitrige zur Wiss. Botanik, i,, p. 2. 
+ Bot. Zeitung, 1863, p. 362. } Lehrbuch, ed. 2, p. 90. 
§ Botanische Abhandl., Pt. 1, 
