MOULD FUNGI 



99 



racemosus (Fig. 30), shows the clustered branching of the sporangio- 

 phore and in addition the hyphae are marked by the intercalary forma- 

 tion of chlamydospores. This mould produces sporangiophores 8 to 20/L1 

 thick by 5 to 40 mm. in height, bearing brownish sporangia 20 to yo/x in 

 diameter. The globular colorless spores are 5 to S/i broad by 6 to lo/i 

 in length. This mould which grows on bread and decaying vegetable 

 matter, and if cultivated submerged in beer-wort, the hyphae swell ir- 

 regularly and a large number of transverse septa appear, which divide 

 the hyphae into barrel-shaped portions. These cells or gemmae can be 

 separated readily, and when free, they become spheric and multiply by 

 budding, as in the true yeasts, and the submerged spores &,lso bud and 

 constitute the so-called Mucor-yeast. At the surface of the liquid, they 

 develop the typic mould form. Mucor racemosus, according to Hansen, 

 is the only mould capable of inverting cane-sugar solution. It produces 

 in beer- wort as much as 7 per cent, by volume of alcohol. Mucor erectus, 

 which grows on decaying potatoes, produces azygospores as well as zygo- 

 spores. It has the same appearance as the preceding and possesses an 

 active power of fermentation. In beer-wort of ordinary concentration, 

 it yields up to 8 per cent, by volume of alcohol, and in dextrin solutions 

 it induces alcoholic fermentation. Mucor spinescens, which grows on 

 Brazil nuts, has spiny projections on the rounded upper surface of the 

 columella. Mucor (Amylomyces) Rouxii occurs in the so-called 

 "Chinese yeast," which is in the form of small whitish cakes, consisting 

 of rice grains kneaded together with assorted spices. These cakes are 

 powdered and mixed with boiled rice upon which the mycelium grows, 

 converting the rice by slow degrees into a yellowish liquid which con- 

 tains glucose produced by the diastatic ferment of the fungus. 



The black mould Rhizopus nigricans {Mucor stolonifer) grows on 

 bread and other organic substrata (Fig. 31). Several sporangiophores 

 arise from a single point of origin, namely, at the top of a mass of rooting 

 (rhizoidal) hyphae which constitute an adhesive organ or oppressorium. 

 Each erect stalk bears oblate spheroidal sporangia with distinct colu- 

 mella and sporangiospores, 6 to 17)1* long. Arising from the base of the 

 clustered sporangiophore is a horizontal hyphae, which often attains a 

 length of 3 cm. and is known as the stolon, or stoloniferous hypha. 

 When the tip of this stolon comes into contact with the substratum a 

 new appressorium is formed from which arises a number of sporangio- 

 phores bearing sporangia (Fig. 31). This method of growth enables the 



