H 



BOTANICAL GAZETTE [january 



0. blandina laeta shows the greatest affinity to 0. Hookeri laeta, 

 not only in the flowers, but also in other respects, as, for example, 

 in the stature at the time of flowering, which in both hybrids comes 

 much nearer to that of O. Lamarckiana than any of the small- 

 flowered hybrid laeta. Far more interesting, however, is the simi- 

 larity in its behavior in the second generation, after self-fertilization. 

 The Hookeri laeta are the only laeta as yet known to split; all laeta 

 of other extraction and all the velutina as yet studied give a uniform 

 progeny. But the Hookeri laeta split in every generation into 

 laeta and velutina which are exactly like the original twins. 9 The 

 same phenomenon is seen in O. blandina laeta , although as yet I have 

 only cultivated one second generation from one cross. This was 

 O. blandinaXO. Lamarckiana , made in 19 13. The first generation 

 in 1914 gave 59 per cent velutina and 41 per cent laeta, and the 

 progeny of the latter split into the same two types in 191 5, giving 

 67 per cent velutina and 3$ per cent laeta. Why the large-flowered 

 laeta should split, but the small-flowered type remain constant, is 

 a question which will have to be studied later. 



O. blandina laeta has been, throughout its whole evolution, 

 exactly the same type in the 3 crosses already mentioned, and whose 

 progeny I cultivated in both years side by side. In the seed pans 

 and the transplanting boxes the young plants are almost exactly 

 like O. Lamarckiana, resembling this form far more than any of the 

 hybrid laeta do. This condition prevails until the beginning of 

 flowering, during which period the leaves of the stem are somewhat 

 broader and less covered with bubbles than in the parent species. 

 This difference is then seen to increase gradually and becomes 

 evident in the lower bracts of the inflorescence, which are broad, 

 especially at their base, smooth, and wholly or almost without 

 bubbles. As the spike develops, the difference from the parental 

 type becomes greater. The fruits are less crowded and somewhat 

 stouter, and the plants gradually reach a greater height than 

 specimens of O. Lamarckiana planted at the same time and under 

 the same conditions. Although the differences are still small, 

 apart from the smoothness of the leaves, the plants of O. blandina 

 laeta cannot be mistaken for Lamarckiana during all the time of 

 flowering, which may last more than 2 months. 



' See the pedigrees in Gruppenweise Artbildung, p. 131. 



