122 MINUTE STKUCTUliK OJ? THE STEM. 



367. The ciibrose portiou of a collateral bunrlle often has, in 

 acldition to true cribrose-cells, prismatic, tliiu-walled cells, known 

 as canibiform cells.^ 



368. According to Vochtiug^ the cambiform and cribrose cells 

 appear in some eases to have a common mother-cell, which di- 

 vides obliquely in the direction of its length. The cambiform 



cells maj- divide by transverse partitions, and if the cells are 

 moderately large the last divisions may be parenchymatous. In 

 most monocotyledons and dicotyledons the cribrose-cells are much 

 larger than the cambiform ones, and their cross-sections are distin- 

 guished by being less sharply quadrangular. In many succulents 

 there are also very small cells resembling undeveloped cribrose- 

 cells. 



369. The cribrose and woody parts of a collateral bundle are 

 generally distinguishable from each other by the lignified char- 



1 Be Bai-y reserves for these cells the tunii Cambiform, which was used by 

 Niigeli in a wider sense. 



^ Beltrage zur Morphologie und Anatomie der Khipsalideen, Pringsheim's 

 Jahi-b., 1874, p. 327. 



Fio. 99. Transverse section of a part of the central cylinder of the mature hypocoty- 

 ledonary portion of the stem of Rioinus communis: r, parenchyma of the primary 

 Cftrtex; m. of the pitli; between r and 6 is the simple endodermis containing starch- 

 grains; the fibro-vascnlar bundle is made up of the phlofe'ni b, y, the xylem g, t, and the 

 cambium c, c ; cb, interfascicular cambium. In the iihloent are the bast-fibres b, 6, the 

 soft bast y, y (partly partjiichynia and partly cribriise-tubes); in tlie xylem, small pitted 

 ducts t, t, wider pitted ducts r/, g, and between them wood-Hbres. (Sachs.) 



