418 BOTANICAL GAZETTE [NOVEMBER 
infected plants, but its distribution may be more or less local. Frequently one 
section of the rhizome with its buds is infected, while the adjacent sections re- 
main free from the fungus. All the leaves arising from the infected sections 
become infected. Experiments like those reported by TIscHLER? for Uromyces 
Pisi, to determine if the plants could outgrow the fungus, were not conducted. 
The mycelium is found in all the tissues except the phloem and xylem; in the 
buds even the cells of the dermatogen are invaded. In this respect the dis- 
tribution of the mycelium in the growing points agrees with that of Uromyces 
Pisi in Euphorbia Cyparissias as observed by DE Bary and TiscHtER. ‘There 
is apparently a marked difference, however, in the behavior of the mycelium 
of these two fungi in the embryonic tissue. TISCHLER observed the interesting 
fact that no haustoria were formed by the hyphae of U. Pisi in the strictly 
meristematic cells, while Dawson states that haustoria are formed in all parts 
of the plant containing mycelium, even “close” to the growing point. Un- 
fortunately neither the description nor the imperfect sketches make this physio- 
ogically — point entirely clear. 
TISCHLER? has published a further contribution to his interesting studies 
on the ation between Uromyces Pisi and its aecidial host Euphorbia Cyparis- 
Sias. is former account the fact was brought out that under certain con- 
ditions se upper portions of infected shoots of this plant might produce normal 
leaves to all appearances free from the fungus. In such cases it was found that 
the growing point had became emancipated from the fungus, which was there- 
after unable again to invade the strictly embryonic tissues. The behavior 
of these shoots is now contrasted with that of shoots from dormant buds 
of infected rhizomes. Such shoots produce only typically deformed leaves 
characteristic of plants infected by the fungus. If, however, the infected 
rhizomes are kept permanently in a vegetative state by pruning or other means, 
the new shoots produced show no external signs of the fungus and bear only 
normal leaves. If infected plants, which as a result of such treatment have 
oi i only normal leaves for a season, are allowed to remain dormant for 
only infected shoots grow out from the dormant buds. It appears, 
therefore, that buds that develop on the rhizome while the plant is kept con- 
subject to such influence and produce only deformed leaves. Nevertheless, 
the apparently sound shoots are not free from the fungus, for the mycelium 
is found in all parts except the meristematic tissue of the growing point; this 
it is entirely unable to invade in shoots which have once become emancipated. 
9 Rev. Bot, GAZ. 56:161. 1913. 
 TiscuteR, G., Uber latente Krankheitsphasen nach Uromyces-Infektion bei 
Euphorbia Cyparissias. Bot. Jahrb. 50:95-110. figs. 6. 1914. 
