190 



LATICIFEROVS TUBES. 



themselves between the neighbouring unlike tissue-elements, and grow out to 

 cylindrical branches, which sometimes remain short, not longer than broad, and 

 sometimes attain a considerable length. Some of these protrusions end blind, others 

 join with similar ones from neighbouring tubes, or with the trunks of these, and 

 open communication is formed by disappearance of the wall at the point of contact. 

 Where two tubes run longitudinally side by side, they are further directly connected 

 by numerous large perforations of the wall of contact. Thus there arises a net of 

 communicating tubes which is usually very complicated, with meshes of most various 

 form and size, and with blind branches of various length and direction, imbedded in 



Fig. 82.— Tangential section from the 

 cortex of Lactuca virosa, with three reti- 

 culately joined milk-tubes (225). 



1-IG. £3.— Scorzonera hispanica ; w slightly ni.ignified tan- 

 gential longitudinal section through the bast of the root. In 

 the parenchyma the reticulately connected milk-tubes ; B 

 piece of a miik-tube and its surroundings, more highly mag- 

 nified. From Sachs* Textbook. 



surrounding — usually parenchymatous — unlike tissue (comp. Figs. 82, 83). This net- 

 work, as above stated, extends throughout the whole plant. Non-reticulate articulated 

 lubes, such as those of Chelidonium, are branched, at least at the points of insertion 

 of lateral ramifications, and send out branches from these points into the latter, 



Sf.cT. 48. The non-articulated laticiferous tubes do not show a net-like 



