. Beginners' botany. Botany. STUDIES IN CRYPTOGAMS 193 each producing a short branch with a httle spo- ridium, s. A most remarkable circumstance in the life history of the wheat rust is the fact that the my- celium produced by the sporidium can live only in barberry leaves, and it follows that if no-bar- berry bushes are in the neighborhood the sporidia finally perish. Those which happen to lodge on a barberry bush germinate immediately, produc- ing a mycelium that enters the barberry leaf and grows within its tissues. Very soon the fungus produces a new kind of spores on the barberry leaves.
. Beginners' botany. Botany. STUDIES IN CRYPTOGAMS 193 each producing a short branch with a httle spo- ridium, s. A most remarkable circumstance in the life history of the wheat rust is the fact that the my- celium produced by the sporidium can live only in barberry leaves, and it follows that if no-bar- berry bushes are in the neighborhood the sporidia finally perish. Those which happen to lodge on a barberry bush germinate immediately, produc- ing a mycelium that enters the barberry leaf and grows within its tissues. Very soon the fungus produces a new kind of spores on the barberry leaves. These are called cBcidiospores. They are formed in long chains in little fringed cups, or cecidia, which appear in groups on the lower side of the leaf (Fig. 283). These orange or yellow aecidia are termed cluster-cups. In Fig. 284 is shown a cross-section of one of the cups, outlin- ing the long chains of spores, and the mycelium in the tissues. The aecidiospores are formed in the spring, and after they have been set free, some of them lodge on wheat or other grasses, where they germinate immediately. The germ-tube enters the Fig. 282. — Ger- minating Te- leutospore OF Wheat Rust. Fig. 283. —Leaf OF Barberry WITH Clus- Fig. 284.—Section through a Cluster-cup on Barberry Leaf. leaf through a stomate, whence it spreads among the cells of the wheat plant. In summer one-celled reddish icredospores ("blight spores," red-rust stage) are produced in a manner similar to the teleutospores. These are capable of germinating Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bailey, L. H. (Liberty Hyde), 1858-1954. New York, The Macmillan company
Size: 1459px × 1713px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbai, bookcentury1900, bookdecade1900, booksubjectbotany
