PERONOSPORALES 207 



1919), Phy. hihernalis Came (1927), Phy. hydrophila Curzi (1927), 

 Phy. jatrophae Jensen, Phy. lepironiae Sawada (1919), Phy. 

 melongenae Sawada (1915), Phy. mexicana Hotson & Hartge 

 (1923), Phy. nicoiianae Breda de Hahn (1896), Phy. paeoniae 

 Cooper & Porter (1928), Phy. parasitica Dastur (1913), Phy. 

 pini Leonian (1925), Phy. richardiae Buisman (1927), Phy. 

 syringae Klebahn (1909), Phy. thalidri Wilson & Davis (in 

 Wilson, 1907 h), and Phy. theohromae Coleman (1910). 



Several genera have been erected on species which do not seem 

 to differ generically from Phytophthora. One of these, Phythia- 

 cystis Smith & Smith (1906: 221) was founded on the causal 

 organism of the destructive brown rot of lemon, Pyth. ciirophthora 

 Smith & Smith, and has remained monotypic. The sexual 

 stage of the organism has not been observed, but the characters 

 of its mycehum and sporangia show it to be intermediate in 

 many respects between Pythium and Phytophthora; the habit 

 being as in the former and the morphology as in the latter in as far 

 as differences may be said to exist. The mycelium in the para- 

 sitic phases on the host plant is always sterile. In the soil or 

 in soil water sporangia occur in abundance. Definite sporangio- 

 phores are not formed. The sporangia germinate by swarm- 

 spores or by germ tubes, in the former case deUmitation taking 

 place in the sporangium and a vesicle being absent. The 

 sporangia are frequently asymmetrical, and two or more papillae 

 of germination are sometimes formed. The authors of the genus 

 and others (Barrett, 1917; Leonian, 1925) have concluded that 

 the species may well be incorporated in Phytophthora. Leonian 

 has recently made the transfer, and the name now stands, Phy. 

 citrophihora (Smith & Smith) Leonian. 



The genus Kawakamia Miyabe (1903: 306) was estabhshed in 

 Japan on a single species, K. cyperi (Miy. & Ideta) Miyabe, 

 found on Cyperus. A second species, K. carica Hara, on Ficiis 

 carica, was described later, and Phytophthora colocasiae Racib. 

 was transferred to the genus by Sawada (1919). The author of 

 the genus regarded it as differing from Phytophthora in that the 

 sporangium in falling away carries with it a small portion of the 

 sporangiophore. He regarded this as a separate cell and termed 

 it the pedicel cell. The sporangiophore was stated by him to be 

 unbranched or only slightly and indefinitely branched. As the 

 original account was inadequate, Sawada (1919) reinvestigated 

 the species, and gives figures which show the genus to agree 



