118 CARPOASCI. 



When a perennial mycelium is wanting, the infection is confined as a rule to 

 white or yellow spots on the leaves, e.fj. the commonest, T. sadebcckii, on Ainu* 

 gliititw*a t and T. aurea on species oiPopulus. T. <alni incanae (Fig. 106) causes 

 considerable hypertrophies on the pistillate catkins of the Alder, which may be 

 compared to the " pockets " of Prunus. 



FIG. 106. TapTirina alni incance on the Aliler (nat. size). 



Series 2. Carpoasci. 



The Carpoasci are Ascomycetes, whose asci are enclosed in fruit- 

 bodies, i.e. ascocarps. The accessory melans of reproduction are 

 free conidiophores (Fig. 109), conidial-layers (Fig. 122), conidio- 

 carps (Fig. 120 D, E, etc.), chlamydospores and oidia. 



For the different methods of distributing the ascospores, see p. 

 92. 



Of the six families of the Carpoasci, the first three Gymnoa- 

 scales, Perisporiales, and Pyrenomycetes are ANGIOCARPIC (that is, 

 the ascocarp remains closed throughout its existence, and does 

 not dehisce when ripe) ; the fourth and fifth families (Hysteriales 

 and Discomycetes), 011 the other hand, are HEMIANGIOCARPIC (the 

 ascocarp, here also called an apothecium, is closed in the early 

 stages, but opens at the commencement of ripening and exposes 

 a hymenium of crowded asci) ; the family of Helvellales has 

 probably GYMNOCARPIC (or hemiangiocarpic) fruit-bodies. 



Family 1. Gymnoascales. 



The ascocarps are surrounded by a spongy and incomplete en- 

 velope. One order, poor in species. 



