. Bulletin. Agriculture. 32 DIMORPHIC LEAVES IN RELATION TO HEREDITY, name "; The species has not been definitely identified, but Mr. F. L. Lewton su^^gests that it may represent Todaro's Gossy- pium microcarpum variet}^ rvfum. The leaves of the Culluche cotton are extremely variable in form, and many of them are quite simple. But instead of being broadly cordate like the simple leaves of Upland or Egyptian cottons, the simple leaves of the Culluche cotton are fusiform or lanceolate, much like the abnormal leaves of the Eg^-ptian cotton shown in Plate IV and text figure 15.
. Bulletin. Agriculture. 32 DIMORPHIC LEAVES IN RELATION TO HEREDITY, name "; The species has not been definitely identified, but Mr. F. L. Lewton su^^gests that it may represent Todaro's Gossy- pium microcarpum variet}^ rvfum. The leaves of the Culluche cotton are extremely variable in form, and many of them are quite simple. But instead of being broadly cordate like the simple leaves of Upland or Egyptian cottons, the simple leaves of the Culluche cotton are fusiform or lanceolate, much like the abnormal leaves of the Eg^-ptian cotton shown in Plate IV and text figure 15. One of the simple leaves of the Culluche cot- ton is shown in figure 17. Comparison of this with the illustrations of the Egpytian cotton previously mentioned will show how close a resemblance of leaf forms may arise in species of cotton that are widely different in other respects. RELATION OF DIMORPHISM TO MU- TATION. Viewed as a phenomenon of heredity, dimorphism of leaves presents an analog}^ with mutative variation. The fact that the abrupt change or contrast of characters occurs in the same indi- vidual plant instead of in separate ])lants should increase the interest attachmg to such variations, especially if it appears that they are of the same general nature as the mutations that give rise to new varieties. The change of characters involved in the production of dimorphic leaves has the most direct analogy with the rather rare })henomenon of bud muta- tion. Cases arc known in which the expression of characters is changed in a single bud of a tree. A single l)ranch of a tree shows a defmite peculiarity not found in other branches or other trees of the same variety. A bud mutation of coffee seen in Guatemala some years ago had leaves as defmitoly unlike the remainder of the tree as any of the numerous seminal mutations of coffee that had been previously Fig. 17.—Simple leaf of Culluche cotton from Tuxtla Gutierrez, Mexico. (Nat- ural size.). Please note that t
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