FUNGI. UREDINEAE. 



J29 



On the leaves of Berberis tnilgaris yellowish swollen spots are found in sprin- where 

 delicate mycehal filaments have formed a dense felt between the cells of the paren 

 chyma (Fig. 85, A and /, the dotted portion between the cells being the mycelium) 

 m these swollen spots are the spermogonia, which make their appearance somewhat 

 earlier, and the aeciclia. The spermogonium (7, sf) is an urn-shaped receptacle in an 

 enveloping layer of hyphal tissue ; hair-like filaments line the cavity, and bursting 

 through the epidermis of the leaf project like a brush beyond the mouth of the spermo- 

 gonium ; the bottom of the spermogonium is covered with short hyphae, the extremities of 

 which give off by abscision a number of small spore-like bodies, the spermatia- it has 

 >een already said, that the part played by the spermatia in the further development of 



FIG. 85. Pttccinia frraminis. A portion of a transverse section of a leaf of Berberis vulgaris with a young aecidium. 

 / transverse section of leaf of Berberis with spermogonia s/r and aeciclia a ; p the peridium ; the leaf is abnormally 

 thickened between K and y, its natural thickness being seen at x. //a number of teleutospores on a leaf of couch- 

 grass ; e its ruptured epidermis, b its hypodermal fibres, t teleutospores. /// part of a group of uredospores u r and a 

 teleutospore t; sh subhymenial hyphae. A and /from nature, slightly magnified, // magn. 190 times, and /// magnified 

 390 times. After De Bary. 



the Fungus is not known. At a later period the aecidia (/, a, a) make their appearance, 

 usually on the underside of the leaves ; they lie at first beneath the epidermis of the leaf, 

 forming tuber-like bodies composed of parenchymatous tissue (A), and like the spermo- 

 gonium enclosed in an envelope of delicate hyphae. In the mature state the aecidium 

 ruptures the epidermis of the leaf and forms an open cup, the wall of which (the peri- 

 dium p) is a layer of hexagonal cells arranged in rows and produced from basidial 

 hyphal branches at the bottom of the cup. The bottom of the cup is occupied by a 

 hymenium, the hyphae of which turn their apices outwards and continually form 

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