384 Lecture on the Parasitic Fungi of the British Farm. 



Examples of spores in cases will be pointed out as we proceed. 

 In a higher state, fungi take a determinate figure formed of a 

 mass of cellular tissue, the centre of which is all spores, attached 

 to it often in fours. This at length dries up, leaving only the 

 dusty spores, as in the case of a common puff-hall. The most 

 completely formed fungi have two distinct surfaces, one of which 

 is even and without any opening, the other separated into plates, 

 called the hymenium, or gills, to which the spores are attached, 

 generally four together, as seen in Fig. 3. 

 Upon these differences of structure de- 

 pend those various attempts at botanical 

 arrangement which I have no time to 

 describe. So numerous are the seeds, 

 spores, or sporules of fungi, that it is not 

 easy to conceive a place whence they are 

 excluded. Those which grow on matter 

 illw * n wn ^ cn decomposition has decidedly 



j |:jM ;; "■' : " h '"''I'] begun, have been well called "the sea- 

 Fig. 3. showing the attachment of vengers of nature ;" but others of a most 

 the Spores in fours. minute description, some of which belong 



to my subject, apparently attack tissues in full health and vigour. 

 With regard to the properties of fungi, 1 can only mention, in 

 a word, that they are respectively eatable, poisonous, medicinal, 

 intoxicating, and even luminous, lighting up with their living lustre 

 mines and caverns where they grow, and in some places assuming 

 at night the appearance of pendulous lamps hanging from the 

 trees on which they vegetate. 



I. I now propose first to describe the chief of those minute 

 parasitic fungi which injure the corn and grasses of this country, 

 premising that corn-plants are themselves only grasses, the seeds 

 of which are sufficiently large for our food. 



These little pests generally present themselves to the unassisted 

 eye under the form of masses of dust, differently coloured, and 

 appear on all parts of the plants, except the roots. 



(1.) The stems or straw of our corn-plants, and also the leaves, 

 are frequently disfigured by a dark series of patches, constituting 

 true mildew, and called by botanists puccinia, from the Greek 

 nuKx, thickly, because of the dense masses of which it consists. 

 It is found upon reed as well as corn, but the microscope reveals 

 a slight difference in the structure of the spores, by which the 

 puccinia of one species of plant is distinguishable from that of 

 another. It was imperfectly noticed by Felice Fontana in 1797, 

 but in 1804 was investigated more closely under the auspices of 

 Sir Joseph Banks, on account of its ravages that season, and 

 microscopical drawings, still in the British Museum, were exe- 



