PLATE XIV.— PEZIZA AND PENICILLIUM. 



Peziza. 



The Tezizse are usually found on decaying vegetable matter, such as rotten wood, old cow-dung, dunghills, and the like. They 

 also grow among moss, and may occur on growing plants. The Spore-fruit, which results from Fertilisation, is disc-like or cup-shaped, 

 stalked or sessile, and may be black or white, red or yellow, etc. The mycelium ramifies through the substance on which it grows ; 

 for instance, the bright green colour often staining as it were decayed wood, is due to these mycelial threads. 



Tig. 1. Piece of rotten wood with Spore-fruits of Peziza upon it 



This specimen is pretty common in such situations, and has a brightly coloured spore-fruit with stiff hairs on 

 its margin. 



Fig. 2. Scrape off with a needle a little of the surface of the spore-fruit, tease out in water, and examine with high power. 



A number of radiating filaments will be seen, many slender, fewer swollen. The slender filaments are barren, 

 while the swollen filaments contain spores to the number of eight. The barren filaments are called Paraphyses, 

 and the spore-bearing filaments Asci (Gr. Askos, a bag), hence the spores are Ascospores. 



Pig". 3. Ascus and Ascospore detached. 



The eight Spores are usually arranged obliquely, following one another, and in the centre of each is a 



Nucleus. 



Tig. 4. Formation of Spores in the Asci of P. confluens. 



In the early stage (a) the small sac is filled with granular protoplasm and a few vacuoles, but no nucleus. 

 Next, a nucleus appears with a nucleolus (fr). By repeated division this original nucleus becomes divided into two, 

 four, and finally eight nuclei (/). The protoplasm now begins to aggregate around each as a preliminary operation 

 in the formation of the spores, until finally the ripe spores are produced (//). Each spore is now surrounded by a 

 firm membrane, the nucleus disappears, and a small oil-globule appears at each end. 



Fig. 5. Reproduction of P. confluens. (The Male and Female organs are coloured artificially — male, red ; female, blue.) 



Adjoining branches of the mycelium form respectively the slender Male organ or Antheridium, and the swollen 

 Female organ or Carpogonium. The free end of the Antheridium comes into contact with the hooked end of the 

 Carpogonium (a), and, as a result of Fertilisation, a Spore-fruit is formed with innumerable spores. This Spore-fruit 

 consists not only of the fertilised Carpogonium, but of an investment of delicate hyphae (6) which grow and branch 

 till they finally form the coloured cup on the surface of which the Asci lies. 



Penicillium. 



Common Green Mould or Penicillium (Lat. penicillum, a painter's brush) is so named from the brush-like form of the fertile 

 hyphae, bearing innumerable gonidia which give the familiar greyish-green hue to the mould. These minute gonidia on reaching a 

 suitable medium are able to germinate, hence it is that the mould spreads with such wonderful rapidity and appears so constantly 

 where the conditions are favourable. But even under unfavourable conditions, the mould can still survive and reproduce itself. If the 

 supply of Oxygen is checked, so that the ordinary course of life cannot be run, then it resorts to a sexual process, just as a plant 

 might throw itself into flower when food-supplies are limited. 



Fig. 6. Remove a small piece of the crust with its green covering and tease out in water. Fertile hyphae may be met with. 



Hypha branching, contents granular with vacuoles, divided here and there by septa. 



Fertile hypha branching regularly, the terminal branches breaking up into gonidia. • The end portion of this 

 small branch rounds itself off and becomes detachable, the new end repeats the same process, and so on till a row 

 is formed. 



Fig. 7. Sow some of the gonidia in a clear fluid, such as Pasteur's, to observe germination. 



The Gonidium at first is spherical, but when germination begins, one or more protuberances appear which grow- 

 in length, divide, and form septa. Continued growth produces a mycelium bearing fertile hyphae, and so the life- 

 history repeats itself. 



Fig. 8. The Sexual process has only been lately discovered, and occurs under peculiar conditions, as yet attained only by arti- 

 ficial means. The Male and Female organs are formed by short branches — the Antheridium being simple and the 

 Carpogonium coiled like a cork-screw. These two come together and produce a Spore-fruit which is about the size 

 of a pin-head. 



Fig". 9. The Spore-fruit is naturally of a yellowish colour, and consists of a mass of Spore-bearing hyphae, enclosed by sterile 

 hyphae. 



Tig. 10. Portion of Spore-bearing tissue removed from Spore-fruit 

 (a) Asci, containing the Ascospores. 

 (o) Ascospore, separate. 

 Fig. 11. Germinating Ascospore producing a mycelium like the Gonidium. 



Life History of Penicillium. — Upright hyphae give off numerous small branches, which become rounded off at their ends to form 

 gonidia. These gonidia germinate and give rise to a new plant This is non-sexual multiplication, but sexual reproduction 

 has recently been discovered by Brefeld. 



When the plant is deprived of air and light, the development of gonidia is interfered with, and sexual organs appear. 

 Two short hyphae lay themselves together — Antheridium and Carpogonium — and the result of their union is a Spore-fruit, in 

 which Spores are afterwards formed, contained in bags or Asci. Each Ascospore may germinate and produce a mycelium 

 bearing aerial hyphae as before. 



