HAGEDOORN, CUCURBITA-STRIJDVRAGEN. 69 
_ hebben gedemonstreerd. Mrs. Hatch THOMAS vond een dergelijk 
geval in tabak. Dit geval bewijst ook nog eens duidelijk, hoe 
gevaarlijk het is, om uit negatieve eigen resultaten te besluiten op 
onnauwkeurigheid van eens anders werk. Nadat Mrs. HAIGH THOMAS 
haar geval had gepubliceerd, gelukte het aan geen onderzoeker 
om parthenogenese bij tabak te demonstreeren, anders dan juist 
bij deze lijn van tabak door Mrs. H. T. gebruikt. Heel waarschijnlijk 
maken kleine verschillen in de omstandigheden, waarin de planten 
groeien, een groot verschil, en het feit, dat zij haar planten in 
potten kweekte en de andere onderzoekers in den vollen grond, 
heeft zeker invloed gehad. 
Berkeley, December 1921. 
Summary. 
This paper is written in answer to Dr. Lotsy’s criticism of our 
work with squashes. Our answer has been delayed mainly because 
the criticism has not reached us at an earlier date. 
Our method of closing buds by means of leadwire, first used 
by CuMMINGS is fully described in view of the fact that our critic 
found bees in flowers so closed by himself. 
In our work, from 105 closed female flowers, on sixteen pure 
forms, no seeds were obtained. The only results were three par- 
thenocarpic fruits. Parthenogenetic seed was produced from hybrid 
plants exclusively. 
The fact that no accidental fertilization can be taken into account 
for our results is proven by: 
I. The absence of seeds from closed buds in non-hybrid plants, 
which plants set seed very freely after they were left to themselves, 
later in the season. 
Il. The fact that from unfertilized flowers on hybrid plants 
either a fruit full of good seed, or a fruit without seed, or nothing 
was obtained, but that the occurrance of fruits with only a few 
seeds was not noticed. 
II. The segregation in progenies from parthenogenetic seeds, 
which always fell within the bounds of what could be expected 
to result from the cross indicated. 
