Varietäten, Descendenz, Hybriden. 211 



ot* Valeriana dioica, distinguished from one another by structural 

 peculiarities of the flower. Among the plants examined by the 

 author four fairly definite types of flower can be recognized. Thcy 

 are 1) short-styled male, 2) long-styled male, 3) hermaphrodite, 4) 

 female. If suitable examples be chosen, there is no difficulty in 

 distinguishing between these four types, but the type forms are 

 connected with one another by a series of intermediate forms. There 

 is therefore absolutely no Sharp line of Separation between succes- 

 sive groups although the intermediate forms are represented in 

 a relatively small number of individuals. In certain male plants a 

 very wide ränge of Variation was exhibited in the flowers borne by 

 a Single individual. 



The difficulties attending the discrimination between the classes 

 render V. dioica an unfavourable subjeet for experimental work. 

 Crosses between any two of the types 1), 2) and 4) gave in F x either 

 a) all three types, b) both parental types and no others, or c) fe- 

 males only. Hermaphrodites were obtained only in crosses in which 

 one of the parents was hermaphrodite. In all the crosses which gave 

 both male and female offspring, there was a large numerical pre- 

 ponderance of females, the ratio being approximately 2,5 5-' ld"- The 

 ratio however maj'- be affected by the power which tnis species 

 appears to possess of producing fertile seed in the absence of polli- 

 nation. In the wild State the males appear greatly to outnumber 

 the females, but this is probably due to the greater opportunities 

 for vegetative propagation enjoyed by the more profusely branched 

 male plant. R. P. Gregory. 



Keeble, E. and Miss C. Pellew. The Mode of Inheritance of 

 Stature and Time of Flowering in Peas (Pisum sativum). 

 (Journ. Gen. I. p. 46—56. 1910.) 



The garden races of Peas include three types, namely tall, 

 half-dwarf and dwarf. The two half-dwarf races "Autocrat" and 

 "Bountiful", crossed together, give a hybrid which is much taller 

 than either of the parent races when grown under the same con- 

 ditions. The F 2 from this cross contains four categories of offspring, 

 namely, plants of the F 1 -type, plants resembling "Autocrat", plants 

 resembling "Bountiful" and dwarfs; the four types oeeur in num- 

 bers which approximate to the ratio 3:3:3:1. The two parent races 

 are distinguished from one another by the thickness of the stem 

 and the lenght of the internode, "Autocrat" having thick stems and 

 short internodes, "Bountiful" thin stems and long internodes. The 

 F x has the two dominant characters thick stem and long internode. 

 The experiments therefore indicate that stature is determined by 

 two factors: the F 1 owes its tallness to the association of these two 

 factors (TtLl), "Autocrat" is Tl, "Bountiful" is tL, and the dwarfs 

 which appear in F 2 are tl. 



Crosses between the same two races throw light on the inheri- 

 tance of time of flowering, „Bountiful" being an early variety, 

 "Autocrat" a late one. The results suggest that lateness is dominant 

 to earliness, but the time of flowering is modified in its expression 

 in the Zygote by the morphological characters of the stem, most of 

 the thick-stemmed plants being late, while the majority of thin 

 plants with long internodes are early. R. P. Gregory. 



