204 



MANUAL OF POISONOUS PLANTS 



ENTOMOPHTHORACEAE 



Mycelium abundant, generally parasitic on living insects ; multi-nucleate, 

 non-septate or may become septate ; asexual reproduction by means of conidia 

 which are cut off from the end of the sporophore; conidium with one or many 

 nuclei; conidia forcibly ejected; sexual reproduction by means of zygospore; 

 azygospores without fertilization also frequent. One of the most common 

 species of this family is the House Fly Fungus Empusa Muscae. Empusa 

 sphaerospenna is found on the larvae of Cabbage butterfly; E. Grylli is on the 

 Rocky Mountain Locust and the Macrospora cicadina is found on the Cicada. 

 Basidiobolus ranarum occurs on frog excrement. 



Fig. 48. Peronosporaceae. White Rust. Albugo canida. 1. Inflorescence of Shepherd's 

 Purse with fungus. 2. Mycelium with haustoria (/i) x 390. 3. Conidiophores and conidia 

 (spores) in chains x 400. 4 and 5. Formation of zoospores in conidia x 400. 7. Oogonium 

 (o) and antheridium (a) attached, mycelium shown below. 8. Oospore with thick wall. 

 9. Germinating oospore forming a zoosporangium. 10. Zoospore. 7-10x400. 6. Ger- 

 minating Zoospore. After DeBary. 



OOMYCETES 



Mycelium occasionally sparingly developed, tubular, asexual; reproduction 

 by swarm spores or conidia; sexual by the formation of oospores in the 

 Peronosporaceae and Saprolegniaceae. 



Synchitrium has a much reduced mycelium. Sexual reproduction found 

 only in some of the genera of the family Chytridiaceae. The non-septate 

 mycelium is reduced to a single sac shaped cell forming a kind of gall in the 

 host plant. One species of Synchytrium, the S. decipiens, occurs on the Hog-pea 

 (Amphicarpaea monoica). 



The family Pythiaceae contains a destructive parasite of seedlings, the 

 Pythium DeBaryanum and the P. proliferum upon dead insects in water. 



ALBUGINACEAE AND PERONOSPORACEAE 



Mycelium generally well developed. Reproduction sexual and asexual; in 

 sexual reproduction oogonia and antheridia : asexual spores, conidia, or zoo- 

 spores. 



