142 



PART II. THE INTIMATE STRUCTURE OF PLANTS. 



[29. 



majus), and in the Bananas (Musa) where, however, the latex is 

 not milky. 



More commonly, as in the Cichoriaceae (e.g. Dandelion, Scor- 

 zonera), the Campanulaceae, and in most Papaveraceae (but not in 

 Sanguinaria, Glaucium, and Bocconia, where the latex is contained 

 in sacs), the cell-fusions take place in all directions, producing a 

 dense network (Fig. 105). 



Structures apparently of the nature of laticiferous vessels occur 

 in certain Basidiomycetous Fungi (e.g. 

 Lactarius) . 



e. Laticiferous coenocytes, commonly 

 known as "laticiferous cells," occur in 

 some Euphorbiaceae (Euphorbieae, Hip- 

 pomaneae), in the Urticaceae, Apocy- 

 naceae, and Asclepiadaceae. As already 

 explained (p. 90), these " cells " are 

 really coenocytes ; they are visible in 

 the early stages of the development of 

 the embryo, and they grow and branch 

 in the tissue as if they were independent 

 organisms (Fig. 106). As they extend 

 from one end of the plant to the other, 

 they attain a very considerable length 

 in many cases. Their walls are fre- 

 quently thickened (e.g. Euphorbia), but, 

 like those of the laticiferous vessels, 

 they are not lignified. They contain 

 protoplasm with many nuclei, which 

 multiply by mitotic division, and in the 

 older parts latex is abundantly present. 

 The latex of the Euphorbiaceae contains 

 curious rod-like or dumb-bell-shaped 

 starch-grains (Fig. 107). 

 Very much elongated structures, somewhat resembling the laticiferous 

 coenocytes just described, have been observed in certain plants, but it is a ques- 

 tion whether they are cells or coenocytes. They may contain tannin (e.g. Elder, 

 Polygonacese), or latex (Cnicus, Carduus, Arctium). 



/. Epidermal Glands. Whilst all the preceding forms of glan- 

 dular tissue are developed in th& internal tissues of plants, some- 

 what similar glandular structures are developed from the super- 

 ficial layer (epidermis), most commonly in the form of hairs (p 64), 



FIG. 106. A portion of a lati- 

 ciferous coenocyte dissected out 

 of the leaf of a Euphorbia. ( x 

 120 : after Haberlandt.) 



