I96 JOURNAL OF THi£ ROYAL HORTICULTURAL SOCIETY. 



in N orf oik. So little did it resemble an ordinary Mirbeckii that Mr. 

 Ames thought that it must be a hybrid * but neither I nor others far 

 more competent to pronounce on such a point see any reason to 

 doubt that it is other than a pure though very freaky example of 

 Mirbcck's oak. I may mention that in the case of this tree, as in 

 that of the one of Sir John Ross mentioned above, the same 

 phenomenon of the red midrib and petiole was observable. 



In the Revue generate de Botanique (1892), vol. iv. pp. 1-6, is 

 to be found a short but exceptionally interesting paper by the well- 

 known French botanist L. Trabut, on the variations of Quercus 

 Mirbeckii in Algeria. He has evidently spent a great deal of time 

 in closely investigating the wide area of that country over which this 

 oak is spread. 



He regards it as very close indeed, to our English oaks, and 

 especially to Q. sessiliflora — indeed, I gather that he looks on it as 

 little more than a geographical variant, and alleges that the points 

 of difference usually emphasized are inconstant and untrustworthy. 

 The best distinction, in his opinion, is the greater number of lateral 

 nerves in Mirbeckii, 9-15, than in Q. Robur, where they are usually 

 6-9, but in the case of Q. Mirbeckii subpedtmculata, of which a leaf 

 is figured in his work on Plate 3, fig. 16, even this distinction disappears, 

 for it has only 8 or 9. Indeed, in the case of the Aldenham examples, 

 I have found it to be as few as seven on each side of the midrib. The 

 plates clearly represent about twenty different types of leaves which 

 diverge to a startling extent. They appear to be sometimes pubescent, 

 sometimes glabrous, some, from dry situations, are small, thick, and 

 leathery, others large, thin, and papery. The older trees at Aldenham, 

 I may here interpolate, are small, but by no means thick or leathery. 

 Some have a sharply pointed apex, some are so rounded off as virtually 

 to have no apex at all ; some, in fact the majority, have a neat regular 

 toothing or " crenellation," as Trabut calls it, on their edges, while 

 others have irregular though not very pronounced lobes. No leaf 

 is figured by him longer than about 4! in., but some are only 1 J in., 

 and in width the variation is from 2 \ to ij in. — in fact, according to the 

 type at which one was looking, one might with equal truth write, 

 " This species has a long narrow leaf," or " This species has a broad 

 short leaf." If all foliage varied to this extent it would be impossible 

 to describe it at all. Some trees, again, are recorded by Trabut which 

 bear large leaves in spring and narrow ones in summer. Mr. Elwes 

 states that the leaves remain green till February or March, and I 

 think this is the generally accepted notion ; but according to Trabut, 

 though it would be easy to select trees with persistent foliage, that 

 is not the usual case in their own Algerian habitat. At Aldenham 

 the leaves of the older trees (about thirty years old) turn brown and 

 fall in autumn. 



Trabut speaks in praise of Coutinho Pereira's valuable study 

 of the oaks of Portugal, in which he treats Mirbeckii as one of four 

 varieties* of Q. lusitanica, the other three being alpesiris, Broteri, 



