332 Hans Winkler. 



in difterent countries, between Zygopetalum and several more or less 

 remote genera, with the result that all the offspring have proved to 

 be Zygopetalum pure and simple. Altogether more than 400 seed- 

 lings have been raised. The seed-parent in each case was Zygopetalum 

 MacMyi (the reserve crosses being unsuccessful). The pollen used was 

 from Odontoglossum Pescatorei. 0. crisputn, 0. grande, 0. bidonense, 

 Oncidium tigrinum, Lycaste Skinneri, Laelia anceps, Calantlie vestita and 

 Vanda caerulea. All the 400 seedlings raised from these matings 

 proved to be exactly like the seed-parent, Z. Mad-ayi. It is inter- 

 esting to note, however, that the individuals raised from the same 

 capsule varied in size and colour of the flowers in the same way 

 that the seed-parent species does in its native habitat. 



In other words, the „false hybrids'* behaved just as if they had 

 been raised from self- fertilised seeds; but, as I showed in 1898, self- 

 fertilisation, direct or indirect, was impossible in these cases, as the 

 pollinia of the seed-parents were all carefully removed, before the 

 crosses were made. Apart from this, too, the peculiar structure of 

 these Orchids makes self- fertilisation impracticable, as Darwin has 

 well shown. Nor is it apparently a case of Alendelian dominance, 

 for in the second generation (F2j the characters of the seed-parent 

 are again repeated pure and simple, even when the „false hybrid" is 

 re-mated with the supposed recessive. This experiment was carried 

 out by Mr. Mc Willi am. by re-mating one of the Fl „false hybrids" 

 {Z. Macliayi Ç X ■^- anceps) with pollen of L. anceps alba, and the 

 result was still Z. Mackayi pure and simple. 



It seems clear, therefore, that we have in these Zygopetalum 

 seedlings, „false hybrids", comparable to the original ones of Mil- 

 lardet (1894) in Fragaria. It may be noted that all the „false 

 hybrids" in Orchids so far are maternal in all characters, as were the 

 majority of Millardet's, and also Bateson and S a und er 's Mat- 

 thiola. Other experiments, however, show that ..false hybrids" may 

 occur that are paternal in all characters, as in a few of Millardet's 

 Fragaria and de Vries Oenothera. 



Whether all these types of ..false hybrids" have a common ex- 

 planation is difficult to say. but so far as the Zygopetalum series is 

 concerned, in 1900 I suggested that the stimulus of fertilisation might 

 induce a kind of parthenogensis, without actual union of the sexual 

 elements, causing the ..false hybrids" to resemble the seed-parent in 

 all characters". 



Diese Ansicht von Hurst, die ja in der Tat eine sehr nahe- 

 liegende und plausible Erklärung für das eigentümliche Verhalten 

 der Zygopetalum -„Bastarde" darstellt, und die auch von vielen anderen 

 Forschern geteilt wird, bedarf natürlich noch der Bestätigung durch 

 die cytologische Untersuchung, die sehr erwünscht wäre. Was sie 



