209 



BRITISH FORMS OF JAS10NE MONTANA L. 

 Br H. W. PimsLEr, B.A., F.L.S. 



The principal object of the present paper is the determination of a 

 •very large-headed and beautiful form of Jasione montanu which I 

 obtained twenty years ago on the sea-cliffs near Ilfracombe. In 

 North Devon, both inland and on the coast, this species is abundant 

 and variable, but the particular form that attracted my attention 

 seemed separable from the smaller-headed plants that 1 regarded as 

 different forms or states of the specific t} r pe. As named varieties of 

 -/. montana have already been recorded as British, it seems desirable 

 to consider these in conjunction with this Ilfracombe form. 



The common sheepsbit, especially as seen in herbaria, generally 

 presents a polymorphic aspect, largely due to variations in habit and 

 hair-clothing. In early summer, when the previous autumn's seedlings 

 first come into flower, the plant, if fairly vigorous, shows a basal 

 rosette of leaves, from which spring a number of suberect, leafv 

 steins, each of which is terminated by a bracteate umbel of flowers 

 borne on a long naked peduncle. In many situations these primary 

 flower-heads quickly disappear, often through browsing animals, and 

 secondary branches, which soon develop flowers, are produced. These 

 in turn are often similarly destroyed and further branching ensues, so 

 that by September the once nearly erect plant has become a decumbent 

 or spreading tuft, irregularly and sometimes intricately branched, and 

 bearing umbels much smaller than those of the primary stems. In 

 these later umbels the bracts are often narrower and more rhomboidal 

 in shape than in the earlier heads, and the aspect of the plant is 

 entirely changed. When the primary stems are not destroyed, very 

 few lateral branches are produced in some forms, while in others these 

 are numerous, springing from the axils of all the upper stem-leaves 

 and sometimes becoming again branched. In the case of plants 

 growing on maritime sands, this varied branching is frequently 

 combined with a more or less prostrate habit, but quite erect forms 

 may be found in these situations. Occasionally, especially in the 

 variety littoralis, the plant may persist and flower a second summer, 

 when it becomes yet more intricately branched. 



The hair-clothing of this species is likewise variable, although the 

 nature of the individual hairs seems uniform and characteristic, these 

 being straight and spreading, more or less flattened, and hyaline or 

 whitish in colour. Hairs are usually present on the surfaces and 

 margins of the leaves of the basal rosette, and are often abundant 

 there. Frequently they are equally numerous on the cauline leaves 

 and the stems, but they always become more scattered on the 

 peduncles. Some forms have the stem glabrate and its leaves only 

 ciliate, or rarely both of these are entirely glabrous. The bracts of 

 the umbels are nearly always pilose on the inner surface, but externally 

 they may be pilose, ciliate, or glabrous. 



At the time of flowering, minute whitish hairs, similar in character 

 to those of the rest of the plant, may sometimes be seen on the angles 

 of the calyx-tube or even over its entire surface, but the}' very rarely 

 Jouknal or Botany. — Vol. 59. [August, 1921.] q 



