HYPHOMYCETES 



1037 



With reference to the name of Family 3, this has been changed 

 from Stilhacece Fries, 1825, to its present name, because Juel has 

 demonstrated that some of the species of the genus Stilbum belong 

 to the Basidiomycetes, and has given the name Stilbella to those 

 left in Fungi Imperfecti. 



The basis of reference with regard to fungi must for all time be 

 Saccardo's ' Sylloge Fungorum,' because it details some 60,000 

 species of fungi, and this is based upon the colour of the hyphse 

 and conidia and the number of septa in the spore, as will be indi- 

 cated when detailing the hyphales. Clements has published a 

 most useful key in English to Saccardo's ' Sylloge.' 



Leaving this form of classification, we will consider Vuillemin's 

 new system. 



Vuillemin's Classification. — Vuillemin has pointed out a diffi- 

 culty which we have also experienced in classifying the fungi of 

 the Hyphomycetes — viz., one and the same fungus may, under 

 different conditions, show a mucedine type, a stilbelline type, and 

 a tubercularine type, which makes its recognition most difficult. 

 To obviate this difficulty he has concentrated his attention upon 

 the ' spore,' in order to form the orders of the class Hyphales, and 

 has given definitions of his terms so as to prevent confusion. 



Terminology. — The following terms require to be carefully 

 studied: Thallospore, Blastospore, Arthrospore, Chlamydospore, 

 Hemispore, Protoconidium, Deuteroconidium, Conidium, Aleurio- 

 spore, Sporophore, Phialide, and Prophialide. 



L The Thallospore is a sporiform element which is really only a 

 portion of the thallus secondarily adapted to the purposes of repro- 

 duction. The various forms of the Thallospore are named Blasto- 

 spores, Arthrospores, and Chlamydospores. 



A blastospore (Fig. 537) is a thallospore, round or ovoidal in 

 shape, developed by budding from the summit or sides of a 

 hypha which may be the same size and appearance as the 

 blastospore, as in Cryptococcus, or may be an elongated 

 filament. 



An arthrospore is a thallospore developed by the disarticula- 

 tion of hyphal elements at first with square cut ends, which 

 subsequently become rounded off, and with thin walls 

 which subsequently become thickened. A Chlamydospore 

 (Fig. 538) is merely a variation of an arthrospore, and may 

 be dej&ned as an intermediate or terminal spore larger than 

 the ordinary hypha, which, without becoming isolated, 

 undergoes a kind of encystment, with the formation of a 

 thick and sometimes coloured wall containing cytoplasm 

 loaded with food material. 



II. The Hemispore (Figs. 539 and 540) starts by a differentia- 

 tion from the thallus, the ' Protoconidium,' but this remains where 

 formed while the hypha continues to grow. Eventually the proto- 



