178 MISSOURI BOTANICAL GARDEN. 



and was therefore followed by drying up and death such as 

 occurs with normal plants later in the season. The plant 

 in the offspring of No. 47, showing virescence, was not ob- 

 served to have virescent flowers until September 29, when the 

 blooming season was nearly past. On this plant the ends 

 of all the branches bore only virescent flowers, while farther 

 down the branches normal seed capsules had been produced. 

 Virescence therefore developd in all the flowers simulta- 

 neously but only appeared at the end of the season. The 

 virescent flowers on this plant became fairly stout branches, 

 in some cases even possessing internodes. 



In the virescent flowers there was no departure from the 

 normal number of parts, but when leaves developed within 

 these they exhibited no regularity in number or arrange- 

 ment, though always growing out from just within the cycle 



of the petals. 



DeVries refers to what appears to be a similar case in 

 Oenothera subovata (1909, p. 423), but does not describe it. 

 He has also described a different type of virescence which 

 is pathological in nature, due to the attacks of certain para- 

 sites. Masters (1869) gives a list of cases of virescence 

 (p. 338) in which he includes Oenothera, with the suggestion 

 that it might perhaps better be called frondescence or phyl- 

 lody. On p. 252 of the work referred to, cases of frondes- 

 cence or virescence of petals in Oenothera striata are cited. 



Polymery of the Flowers. — A number of cases of flow- 

 ers with an increased number of parts were observed in the 

 cultures of 1909 and 1910. No special effort was made to 

 find them all, but they were recorded as they happened to 

 be observed by myself or my assistant. Masters, on p. 44 

 of the work above cited, refers to species of Oenothera as 

 exhibiting synanthy. Many of the cases of polyphylly in 

 flowers of Oenothera, to be described shortly, are due to 

 synanthy, as I shall show. Certain other cases will require 

 a different explanation. 



DeVries (1909, pp. 472, 482) has recorded a number of 

 cases of polymery from his cultures and in the field at 



