236 BRITISH FLOWERING PLANTS chap. 



flowers do not fade as soon as they are fertilised, but 

 retain their clear colour until the male flowers, which 

 do not open till several days after the female, have shed 

 their pollen. The flowers are succeeded by the soft 

 white pappus. The plant is perennial, developing its 

 flowers early in the spring, and later the leaves, which 

 are often very large. It spreads widely by means of 

 burrowing stolons. The stem is somewhat woolly. 

 The stomata are on the under side of the leaves, and 

 are protected by a loose white cottony wool. 



T. Petasites (Butter-bur). — In this species the male 

 and female flowers are, as a rule, on different plants. 

 There are sometimes, however, a few female florets on 

 the male and a few male florets on the female plant. 

 The male has smaller flower -heads and a looser panicle. 

 The male flowers are tubular below and expand into a 

 bell above. They secrete honey. They have a pistil, 

 which is necessary to brush out the pollen, but which 

 has no stigma. The female flowers are tubular and 

 honeyless. They have not a trace of stamens, and the 

 outer sides of the stigmas have some short hairs which, 

 however, can hardly be said to amount to a brush. 

 The stem is somewhat woolly. The leaves are char- 

 acteristic, and perhaps our most remarkable example, 

 of those adapted to situations in which the supply of 

 water is considerable, the air moist, and the light not 

 too strong. They are very large, sometimes almost a 

 yard across, flat, smooth, delicate, and glabrous. As, 

 moreover, they grow where leaves are abundant the 

 plants have comparatively little to fear from browsing 

 quadrupeds. In dry arid regions such as the Riviera 

 such leaves would not last a day. To the same type 

 belong those of Dentaria (p. 80), Orobus, Paris, 

 Lunaria, Mercurialis perennis (Dog's Mercury), Arum 

 (Lords and Ladies), Impatiens (Balsam). 



The Butter - bur is often separated as a distinct 

 genus, Petasites, when it is known as Petasites vulgaris. 



