MILDEWS, RUSTS AND SMUTS 
95 
Syn. Uredo linearis, var. polypodii, Pers. 
Uredo filicum, Desm. 
Uredo scolopendri, Fckl. 
Parasitic on the fronds of various kinds of ferns. Scolo- 
pendrium vidgare, Polypodium dryopteris, Blechnum spicant, 
Cystopteris fragilis, Adiantum capillus-veneris. 
PUCCINIA, Pers. 
Pycnidia, when present, generally appearing on the upper 
surface of the leaf, subglobose, honey-colour ; spores very 
minute, globose or elliptical, colourless. 
Aecidia, when present, generally globose and closed when 
young, then expanding and becoming cup-shaped or 
C3dindrical, usually with a distinct wall enclosing the spores, 
which are produced in chains, which soon break up, sub- 
globose, wall usually colourless, contents orange or yellow. 
Uredospores. Sori, when present, usually minute ; spores 
produced singly on slender sporophores, subglobose or ellip¬ 
tical, germ-pores two or more, rarely only one. 
Teleutospores. More or less elongated, i-septate, borne 
singly on more or less elongated sporophores, frequently 
accompanied by paraphyses, each cell of the spore has one 
germ-pore. Produced in sori of variable size, usually 
blackish. 
So far as the British Flora is concerned, the species of 
Puccinia are at once distinguished from all other rnembers 
of the Uredinaceae by the constantly 2-celled teleutospores. 
All the species are true parasites, and some prove very 
destructive to cultivated plants, as wheat rust, holl3/hock 
disease, etc. 
COMPOSITAE 
ACHILLEA 
Puccinia millefolii, Fuckel, Plowr., Brit. Ured., p. 215. 
Teleutospores. Sori minute, rounded or irregular, generally 
scattered, dusky brown, on both sides of the leaf; spores 
club-shaped or oblong club-shaped, tip rounded or slightly 
pointed, thickened, constricted at the septum, smooth, 
pale brown, 35—50 X 13—19 p, pedicel stout, persistent, 
rather long. A few mesospores are sometimes found in a 
sorus of teleutospores. 
On living leaves of yarrow— Achillea millefolia. Britain, 
Germany, Austria, Hungary, Italy, Belgium, and Holland. 
