' - 



V 



BULLETIN 



OF THE 



TORREY BOTANICAL CLUB 



Vol. IX.l New York, February, 1882. [No. 2. 



On a Hybrid Oak near Keyport, N. J. 



By N. L. Brixton. 

 (Plates X, xr and xii.) 



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Wm. Bower, while botanizing between South Amboy and Keyport, 

 New Jersey, noticed a number of oak-trees whose leaves and acorns 

 seemed different from those of any species known to grow in the 

 vicinity of New York, and which apparently indicated every form of 



Q 



Q 



Since the date of the discovery of the trees, two other excursions 

 have been made to the locality by members oi the Torrey Club, and 

 the result has been a confirmation of the impression first formed, and 

 all who have seen them are of the opinion that they are hybrid forms 

 between the black-jack and willow-oaks, and, as such, have not been 

 noticed in our botanical literature up to the present time, as far as I 



can ascertam. 



The number of trees observed was about ten, of widely different 

 ages, indicating either that the process of hybridization has been in 

 progress at different times, or, that if it all took place the same sea- 

 son, some of the acorns have germinated sooner than others. 



• The outlines and modes of venation of the leaves of the new hv- 

 brid are exactly represented in the accompanying plates. 

 These show the principal variations towards the unlobed or 

 slightly lobed leaves of typical Qiiercus nigra, L., and ^ the 

 much-lobed leaves of what Dr. Engelmann regards as a juvenile, 

 sterile state of the same tree, but which is often seen in 

 large fruiting specimens — the Q, ferrughtea of Michaux. These 

 leaves vary in outline from lanceolate or oblong unlobed leaves 

 (Figs. 2 and 6), not unlike those of Q. imbricaria^^ Michx., to those 

 where a slight, obtuse lobe appears on on^ side (Fig. 3) ; or slight on 

 one side and more pronounced on the other (Fig. 4) ; or well marked 

 on both sides (Figs. 5 and 7) ; or obtuse ovi. one side and acute and 

 bristle-pointed on the other (Fig, 9) ; or acute and bristle-pointed on 

 both'sides (Fig. 10), to the leaves of Q, nigra, L. (Figs. 8 and 11). 

 It appears as though the specimens reproduced on Plates x and xi 

 were transitions towards the slightly lobed or unlobed Q. nigra, L., 

 while the two lower figures on Plate xti indicate transitions towards 

 the more loh^d forms ; and the figures have been grouped with re- 

 gard to this fact The petiole is also seen to vary, though not very 

 prominently shown in the leaves figured, from very short in Phellos 

 to a considerable length in nigra. The amount of pubescence on 

 the lower surface of the leaves, very slight or absent in Phellos^ varies 

 on leaves of the hybrid to the heavy, rusty covering of nigra. 



