46 Transactions. 



reduced in size, as in V . diosmaefolia R. Cunn., a heath-plant — indeed, there 

 are few species whose leaf-form cannot be referred to evident epharmony. 



The general habit of the species is often strikingly epharmonic. In 

 point of fact, all branch on the same plan, but density or looseness of 

 branching in its extremes makes very different plants, as in the far-spread- 

 ing, open, and stragglingly branched V. Cookianum Col. and V. Dieffen- 

 bachii Benth., and the close ball - like V. buxifolia var. odora T. Kirk, 

 V. Traversii Hook, f., and many of the subalpine semi-xerophytic species. 

 Still more xerophytic species have the prostrate form, as V. chalhamica, 

 a plant of wind-swept and spray-swept coastal rocks, and V. ■pinguifolia 

 Hook, f., in some of its numerous forms, as it hugs dry alpine rocks or the 

 stony surface of fell-field. It is instructive, too, to see how one and the 

 same Linnean species varies in the growth-forms of its components. Thus 

 V . buxifolia Benth. may be either a ball-like shrub, a low erect open little- 

 branched shrub, or sparsely branched and prostrate. Its leaves, too, vary 

 from patent to imbricating ; while as for small leaf- variations, they are with- 

 out end. The degree of imbricating of leaves is a striking epharmonic 

 feature in these small-leaved veronicas, and Cheeseman uses it, but in a 

 guarded manner, as an aid to identification. But the truth is, the indivi- 

 duals of a well-defined form vary much in this regard according to their 

 surroundings, while there appears also to be non-epharmonic variation of 

 this character. 



A more xerophytic station in general than that of the subalpine species 

 of class 1 is demanded by those of class 2. Here reduction of leaf and 

 imbricating reach their maximum in the whipcord forms. These have fully 

 developed though small leaves as seedlings and on reversion shoots, and 

 are thus united to Veronica Gilliesiana, T. Kirk, Hook, f., and others whose 

 leaves are not so much reduced. Classes 1 and 2, as here defined, seem to 

 be connected by V. buxifolia Benth., as a study of its seedling form shows.* 

 But this latter is also related to V. cassinioides Hort., which, as already 

 shown, is a juvenile or ancestral whipcord Veronica which may be linked 

 with suffruticose and herbaceous species by V. loganioides J. B. Armstg. 

 The relation, then, if my supposition be accepted, between such a species 

 as V. buxifolia or some form such as V. cassinioides is so close that favour- 

 able epharmonic conditions should convert the one into the other in course 

 of time. The cupressoid growth-form of these whipcord veronicas may 

 easily have appeared epharmonically several times. Each time there 

 would be some slight difference in the form evoked, and thus some of the 

 species of whipcord Veronica may have originated independently and not 

 from one ancestralf cupressoid form, and there may have been actual 



♦Details are given by me (1901, pp. 282-86) under the name V. odora Hook, f., 

 which, however, is now known through the researches of Cheeseman (1909) to be distinct 

 from the plant in question, which is V. buxifolia Benth. var. odora T. Kirk. PI. 11 

 in the above paper should be consulted, as it shows the relation in form between the 

 juvenile leaves of V. buxifolia var. odora and V. Armslrongii T. Kirk, a whipcord Veronica. 



•f Regarding polygenetic origins, Chilton wrote (1884, p. 156), " Suppose the 

 marine ancestor of the terrestial Isopoda to be widely spread, and to inhabit the shores 

 of, say, New Zealand and England, and that in each case certain animals began gradually 

 to leave the sea and make their home on the land, at first keeping within the range of 

 the spray, as Ligia still does, but afterwards leaving the sea altogether, would not the 

 new conditions in which these animals would be placed, being practically the same in 

 both countries, produce in each case the same effect, so that the variations which would 

 be preserved would bo the same in the two cases, and hence the animals, although arising 

 independently from the same marine ancestor, might so far resemble one another as to 

 be placed in the same genus or even in the same species ? " Guppy (1907) should also 

 be consulted. 



