52 071 Hybridisation of some Species of Salix 



two hybrids and many M. ruhrum, i.e. plants of purely maternal type. 

 In some species of Fragaria Millardet^ got plants of both paternal 

 and maternal types by hybridisation — the well-known "hybridation 

 sans croisement" or "fausse hybridation 2." This was repeated on 

 Fragaria virginiana ^ x F. elatior ,} by Solms-Laubach, who got hybrids 

 of purely paternal type, thus confirming the results of the French 

 author ^ The same kind of hybrids as the latter were found recently by 

 Collins and Kempton in the Gramineae Trifsacii'm dactyloides $ x 

 Euchlaend meadcanaj*, which breeds true in later generations — what 

 these authors call " Patrogenesis^" 



Hybrids of purely maternal type were obtained by Hurst from the 

 Orchid Zygopetalum Mackayi fertilised by some species of Odonto- 

 glossum, Oncidium and Lycasta^. 



A very detailed study was made by Lidforss on a great number of 

 species of Rubus^. According to him the hybridisations, R. acuminatus, 

 R. divergens, R. dissimulans, R. plicatus as females by R. caesius as 

 male, and R. polyanthemus as female by R. Bellardi or radula as males, 

 for instance, have given genuine and false hybrids in nearly equal 

 numbers, whilst the hybridisations, R. polyanthemus, R. insularis, 

 R. Lindenhergii as females by R. caesius as male have given rise ex- 

 clusively to false hybrids. The false hybrids of Lidforss were always of 

 purely maternal type, and were found to breed true in later generations. 



To cite another example, de Vries obtained by the hybridisation 

 Oenothera Lamarckiana $ x 0. biennis ^ false hybrids of paternal type, 

 which were found to breed true in later generations''. The same 

 hybridisation carried on in the New York Botanical Garden has given 

 quite different results, because it has given rise to four distinct types 

 of hybrids (MacDougal, Vail, Shull and Small)^, and the latter four 

 authors came to the conclusion that the difference of their results from 

 those of de Vries might be due to the influence of some factors, such 

 as individual qualities as well as external conditions. It might however 



1 Mimoire de la Soc. des Sciences physiques et naturelles de Bordeaux, 4 S6rie, torn. iv. 

 • 1894, pp. 347—372. 



2 Besides Fragaria false hybrids were observed by Millardet in Rubus (I.e.) and Vitis 

 (Revue de Viticulture, torn. xvi. 1901, the original paper not seen, reviewed in Winkler, 

 Prog. Rei Bot. Bd 11. 1908, p. 344. 



3 Bot. Zeit. I. Abt. Jahrg. 65, 1907, p. 53. 



4 Journ. of Heredity, Vol. vii. 1916, pp. 106—118. 



5 Journ. R. Hort. Soc. Vol. xxix. 1900, pp. 104—106. 



6 Zeits.f. ind. Ahstammungs- und Vererbungslehre, Bd xii. 1914, pp. 1 — 13. 



' Die Mutationstheorie, Bd 11. p. 31, and Gruppemveise Arthildung, pp. 156 — 159. 

 8 Carnegie Inst. Washington Publ. No. 24, 1905, p. 17 ff. 



