Refrodncfivc Organs. 



CHAPTER III. 



Reproductive Organs — Spor us. 



Just as ill the Rusts, the spores form the most prominent feature and play a 

 most important part in the determination of the species. Hence they have 

 received a hirge share of attention at the hands of investigators, and will 

 require to be carefully studied in their various bearings. There is a good 

 deal of confusion in the use of the term spore, since it may be applied in a 

 general way to all the reproductive bodies of these fungi, and in order to 

 fix definitely the exact position it occupies in the course of the life-history 

 a qualifying word is often prefixed to it. We refer to the spores which arise 

 in the form of a dark powder, and to which the familiar name of smut or 

 bunt is given. 



Since the spore and its products are constantly being referred to, the 

 terms generally employed to designate them may be appropriately given 

 here, indicating at the same time those which will be commonly adopted 

 in describing the life-histories of the various species. As members of the 

 great group of Fungi, the smuts have necessarily much in common in their 

 vegetative and reproductive processes with the others, and there are conse- 

 quently general terms which are applicable to all, but, on the other hand, 

 there are special characters which distinguish them from the others, and to 

 express these distinctions special terms have been employed. The names 

 given will vary according to the different views held as to their relationships, 

 and they will presuppose affinities which may, or may not, be borne out by 

 facts. The following scheme shows at a glance the various names given to 

 the spore and its products by prominent investigators of this particular 

 group : — 



General terms — Spore= ^ terminal Tube= Conidium= 



Special terms — Promycelium (Tiilasne and Sporidium (De Bary) 



Resting-spore (De Baiy) | De Bary) , Conidinm (Brefeld) 



Olilamydospore (Brefeld) \ Hemibasidinni (Brefeld) Sporidiolum (Saccardo) 



Teleutospore (Plowright) j ! Promycelial spore (Tulasne) 



As regards the spore itself, De Bary calls it a resting-spore, because it 

 usually undergoes a period of rest before germination, and Brefeld speaks of 

 it as a chlamydospore, on account of its firm membrane, while Plowright 

 regards it as a teleutospore, being the supposed equivalent of that spore 

 in the Uredineae. Amid all this diversity of naming we will simply call it 

 a Spore, as it is the main reproductive body, and the other spore-like bodies 

 derived from it will receive special designations. 



The spore on germination produces one or more germinal tubes of the 

 nature of a hypha. This hypha may either elongate, branch, and become 

 the foundation of the mycelium, or, as in the Rusts and Smuts, it may 

 be very limited in its growth, and give rise directly to other spore-like bodies 

 unlike the mother-spore, and then die off. On account of this special 

 feature of the product of germination in the Rusts, Tulasne called it a 

 Promycelium, because it represented a mycelium in a very abbreviated form, 

 and because a similar short and short-lived germinal tube was produced 

 in the Snmts, De Bary likewise gave it the name of promycelium. But 

 Brefeld introduced the term hemibasidium to indicate the relationship which 

 he considered to exist between the Ustilagineaj ai;d the Basidiomycetes. 

 The name of promyeeUum. however, is distinctive without involving any 

 particular view of relationship, and will be adopted here (Plate I.. Is). 



