GENERAL INFORMATION 



5 



usually dark coloured ; and the hyphce forming them 

 are rich in food substances. They constitute a 

 resting stage, in that they can withstand cold, 

 drought, etc. ; and after a longer or shorter period 

 of rest, are capable of starting growth (see p. 55, 

 under ergot). When sections of sclerotia are ex- 

 amined under the microscope they resemble, to 

 some extent, the tissue of the higher plants. 





A 



E3 





Fig. 3. — (A) Sclerotiuin of Clavueps pnrpui'ea (Ergot) ; (B) Sclerotium 

 of Sclerutinia trifoliornm ; (C) Is a section through a sclerotiuin 

 showing cell-like appearance, somewhat diagrammatic and highly 

 magnified. 



HaiLstorla (Suckers). — Parasitic fungi which live 

 on the surface of the host plant (e.g. Erysiphc), and 

 many of those living in the intercellular spaces (e.g. 

 Piiccinia graininis), are provided with special organs, 

 for the absorption of food, called haustoria, or 

 suckers. 



These haustoria are modified portions of the 

 hyphae, and are of no fixed form (Fig. 4). In the 

 Erysiphacece they consist of foot-like expansions 



