PESTS OF THE FLOWER GARDEN. 



5 



subglobose spores, termed tTcidiospores, produced in chains, but soon 

 falling apart (PI. I. fig. 21). The recidiospores will germinate when mature 

 and produce a thread of mycelium, which is capable also of producing 

 secondary spores (fig. 1). Smaller bodies are also to be found in company, 

 or in proximity, sometimes on the opposite side of the leaf. These have 

 the form of minute embedded cells, containing very small hyaline spore- 

 like bodies called spermatid, whilst the cells which contain them are 

 spermogonia. What their function may be is as yet only conjectural, but 

 they are nearly always present, and, presumably, not without a purpose. 

 Later on in the summer the same leaves, or others, develop on either or 

 both surfaces small brownish pustules, at first covered by the cuticle, but 

 at length splitting irregularly and exposing a powdery brownish dust- 

 like mass of nearly globose spores, each spore borne at first at the apex of 

 a short hyaline thread, these threads arising from a cushion-like base of 

 mycelium. These powdery spores constitute the " rust," or uredospores 

 (PI. EE. fig. 226), and with them ends the second stage of the fungus ; but 



Fig. 1. — zEcidiospore germinating. 



how they are evolved from the first stage, or how they produce the third 

 •stage, is a mystery still. 



The third is held to be the complete or perfect stage, and the spores 

 produced are teleuto spores, or final spores. These teleutospores are more 

 or less elongated, divided by a septum across the middle into two cells, 

 and supported upon hyaline sporophores or spore-bearing threads (PI. II. 

 fig. 22c). They are produced in pustules similar to those of the uredo- 

 spores, but often more compact, and are sometimes mixed with them. 

 A few of the teleutospores will sometimes be found growing within the 

 pustules of the uredospores. When the teleutospores are mature they 

 do not always germinate at once, but a period of rest supervenes, and 

 perhaps they may not germinate until the following spring, becoming, in 

 fact, veritable resting spores. This is an important fact to be borne in 

 mind by the cultivator. 



Each cell of the teleutospore is capable of sending out a germ tube 

 through a special pore, and as this germ tube grows, the contents of the 

 cell of the teleutospore passes into the germ tube, known also as the 

 promycelium, and to the extreme end. Ultimately a septum, or division, 



