Fig. 205.
Ripe oospore of Peronospora alsinearum.
398. In sexual reproduction oogonia and antheridia are developed on the mycelium within the tissues. [Fig. 204] represents the antheridium entering the oogonium, and the male nucleus fusing with the female nucleus in fertilization. The sexual organs of Phytophthora infestans are not sufficiently known.
399. Mucor, saprolegnia, peronospora, and their relatives have few or no septa in the mycelium. In this respect they resemble certain of the algæ like vaucheria, but they lack chlorophyll. They are sometimes called the alga-like fungi and belong to a large group called Phycomycetes.
[CHAPTER XX.]
FUNGI CONTINUED.
“Rusts” (Uredineæ).
400. The fungi known as “rusts” are very important ones to study, since all the species are parasitic, and many produce serious injuries to crops.
