192 TRANSACTIONS OF THE [Sess. lxxvii. 



radiate. This delayed scape evolution is morphologically 

 interesting in relation to the dispute over the development 

 of the inflorescence in the common primrose, P. acaulis, 

 Hill. In the typical primrose plant, as you are aware, 

 there is no scape such as is found in the cowslip, P. 

 officinalis, Hill, or in the oxlip, P. elatior, Hill. But there 

 is a plant, found wild in several areas in Europe — in 

 Denmark, Germany, Austria, Switzerland — and named by 

 authors P. acaulis, var. caulescens. It has been in the 

 past regarded as a form of the primrose in which the scape 

 is developed. In these days when the fashion is to " solve " 

 or " burke " riddles of form by using the word " hybrid," 

 this plant has become a " hybrida secundaria " (acaulis x 

 elatior). I do not profess to give an opinion upon the 

 issue of " delayed development versus hybrid." All I will 

 say is, as bearing upon this point, that here in this species 

 P. Lacei, Hemsley et Watt, we see an example of postponed 

 scape evolution which shows that the phenomenon does 

 appear in the genus, and so far as I know there is no 

 experimental proof by hybridisation of the production of 

 the form called of old P. acaulis, var. caulescens ; yet its 

 occurrence in the area over which it has been found in 

 nature would suggest that such an artificial hybrid should 

 be an easily produced one. 



The flowers in most of this suffruticose section are 

 yellow. In P. Forrest ii, Balf. fil., the only one in cultiva- 

 tion for study, there is variation from pale sulphur-yellow 

 to an intense golden colour, and the richness of the latter 

 is most striking. Two species, P. Monbeigii, Balf. fil., 

 and P. Dubernardiana, G. Forrest, from the Tibetan 

 frontier, have rose-coloured flowers larger than those of 

 the yellow type. 



In the construction of the flower there are two forms 

 amongst the species I include in the group. All of them 

 have a calyx which is somewhat sclerosed at the base — 

 the part will ultimately subtend the fruit — but the calyx 

 never becomes concrescent with the fruit. Whilst most of 

 them have a tubular campanulate calyx cut to a varying 

 depth, in P. Lacei, Hemsley et Watt, the campanulate 

 calyx hardly forms a tube. With the latter character is 

 associated an extended development of the corolla-tube, so 





