2 TIIK JOURNAL OF BOTANY 



some have and some have not spots or rings. Even when hotli 

 parents have spots, it is just possible that some individual arising 

 from the cross might he unspotted. 



It is necessary first to consider the connection of 0. pratermissa 

 Druce with O. latifolia L. If Rolfe is right, the former is nothing 

 but "true" latifolia. It is interesting to note that the botanists of 

 Winchester College had discriminated this plant as a second type of 

 O. incarnata. On this, see Bot. Soc. & Exch. Club Report, 1917, 

 p. 174, and the whole article \>y Dr. Druce on the British Palmate 

 Orchids. Another form with unspotted leaves has also to be con- 

 sidered. This is abundant in Scotland, and, in our view, sin Mild he 

 placed under O. prcetermissa, from which it differs in having a richer 

 purple colour of the lip, with much heavier markings, and often 

 slender narrow leaves. Although called by Druce "northern incar- 

 nata," it must be distinguished from the plant which he has named 

 O. incarnata v. pulchella *. 



We regard 0. prcetermissa as certainly a distinct species, the 

 identification of which is a great advance towards the complete 

 elucidation of the puzzling forms of the Palmate Orchids. If this 

 species, as well as the "northern incarnata " be ruled out, we are left 

 with a number of types of O. latifolia, of which most individuals 

 have spotted leaves. The lip-types of O. prcetermissa and of its 

 " northern " form are given in Journ. Bot. 1920, pt. 556, figs. 5-8. 



In discussing the varieties of O. latifolia the question arises as 

 to whether, the unspotted forms being eliminated, we have a true 

 species left, and not a mere congeries of hybrids. As regards British 

 forms, this opinion appears to be tending to dominate, and it may be 

 venturesome to resist it. Yet we do not think the question by any 

 means decided in that sense. Dr. Druce (B. E. C. Club Report for 

 1917, p. 1G9) says, " It is evident that much further field-work will 

 have to be done before it is safe to reject latifolia as a British plant." 

 Perhaps he would to-day grant even less than this. Dr. Heslop 

 Harrison has found O. latifolia in Durham, in profusion, far from 

 other plants. Winchester botanists, quoted by Druce (I. c. p. 175), 

 consider that O. latifolia " is distinct from evident first-generation 

 hybrids, and possibly exists as a constant species in places where 

 one of the so-called parents does not any longer exist. It may 

 possibly represent the result of hybrids self-fertilizing for some 

 generations and so producing in time a type breeding true, but this 

 point again must be decided by experiment." This statement is open 

 to some criticism from the Mendelian standpoint, since, if a type 

 breeds true it is not due to any time-factor, but to the homozygous 

 character of the uniting germ-cells. Another suggestion (I. c. p. 177) 

 is " that the Marsh Orchids constitute either a recent group which 

 has not yet settled down into a well-defined species, or else a species 

 that has become variable and is breaking up into three types." Two 

 quite distinct points have to be dealt with, one whether O. latifolia 

 is ever found growing apart from other forms, in such numbers and of 



* Dr. Druce has now published a description of this form in B. E. C. Eeport, 

 1919, p. 577. He names it 0. prsetemvissa v. pulchella, as it is closely similar to 

 the v. pulchella of 0. incarnata already so named by him (B. E. C. Eep. 1917. 

 p. 167). 



