Pethybridge & Lafferty — Disease of Tomato and other Plants. 505 



Plate XLVII. 



Fig. 1. Mycelium of Phytophthora cryptogea from a 30-day-qld culture on maize 

 meal agar. The slight constriction of the lateral branches at their 

 points of origin is rather characteristic, x 510. 



„ 2. Three immature sporangia from sporangiophores developed in water 

 from mycelium in the affected portion of a young tomato plant 

 artificially inoculated from a pure culture, x 510. 



„ 3. More mature sporangia from the same source. The one on the left 

 ripe, the one on the right about to liberate its zoospores, x 510. 



„ 4. Sporangiophore and sporangia from the same source. The branching 

 is sympodial, but the branches are unusually short, x 510. 



Figs. 5 and 6. Sporangia produced by the fungus when growing on roots 

 of Cheiranthus (after artificial inoculation). The upper sporangium 

 in fig. 5 has commenced to develop a germ-tube. In fig. 6 the germ- 

 tube is in a more advanced stage of growth, x 510. 



Fig. 7. Two cases of the development of a second sporangium from within 



the base of the first formed one. x 510. 

 „ 8. Development of a third sporangium within two previously formed 



sporangia, x 510. 

 „ 9. Mycelium of P. cryptogea as developed occasionally from diseased 



portions of the host when submerged in water and also in pure 



culture, representing, possibly, abortive attempts at the production 



of sporangia or of sexual organs, x 510. 



„ 10. Sporangium in which each zoospore-unit has developed a germ-tube 

 without the liberation of free zoospores, x 840. 



., 11. Sexual organs of P. cryptogea from a 6-weeks-old pure culture on hard 

 Quaker Oat-agar. x 740. 



12. Sexual organs of P. crythroseptica for comparison, x 740. 



JUN15 



SCIENT. PROO. E.D.S., VOL. XV., NO. XXXV. 



4K 



