PROTOMYCES. 



139 



distributing- itself through the intercellular spaces, stimulates the 

 parenchyma-cells of the host to growth and cell-division. The 



Fig. -i'L—Protomyceg macrosporus on leaf-st;ilk of AeriopoOivni Poiiopraria. 

 A, Jlycelium and sporangium in the tissiie under the epidermis. B, Sporangia 

 in stages of development, (v. Tubeuf del.) 



latter is a secondary process and consists (see Fig. 9) in the 

 formation of exceedingly delicate membranes inside the original 



Fig. iG.—Protomi/ces macrosporus. Section of petiole of At(jopodium with two 

 swellings containing spores. Secondary cell-walls have been formed, and a 



collenchj-ma region lies between the two swellings, (v. Tubeuf del.) 



cells of the parenchyma, so that they become divided iiil" 

 younger cells rich in protoplasm and each ,sho^ving a distinct 



