PLANT HAIRS 



r.v K. E. STVAX. 



{Continued front I'agc /JO). 



Part \I. — un Haikv Awxs and (/?) Pappuses. 



Ix the threat work of dissemination of fruits and 

 seeds which is being carried on hv \arioiis agencies, 



^^ - dail\', over the length and 

 breadth of the world, 

 hairy outgro\\ths play 

 a very important part : 

 for they ensure the 

 structures on which thev spring 

 being wind-wafted, whether or 

 no the\" take the form of true 

 coverings to the seed, "pappuses," 

 or feather\-, silkv aw ns. or append- 

 ages. Usualh' the hairs found on 

 seeds and fruits are extremely 

 numerous, so numerous that it is 

 3^- quite out of the question to attempt 



to count them, but instances do 

 occur in which onl\- quite a 

 limited number are present, of 

 which one good example may be 

 seen in the case of a plant called 

 Aeschynanthiis, whose fruit onl\- 

 bears three hairs on it. one on one 

 side and two on the other. But 

 these three are specially adapted 

 for the great use to which the\' 

 are called into being h\ being 

 remarkably flexible, which not 

 only causes them easily to adhere 

 to, but also to curl round the wool 

 or fur of animals after they ha\e 

 been wafted bv the ^\ind on to 

 the creature's body. Thus the 

 hairs in this case cause the fruits 

 to be disseminated both b\- wind 

 agenc\" and animal conveyance. 

 Exquisitely beautiful are manv 



FiGL-RE 1. 



Awned acheiic of 



Sfripii pciinata 



(two-thirds natural 



size). 



of the hairy prolongations that are found. Our 



hedgerows in autumn are made charming b\- the 



presence of silvery clusters of wild 



clematis (see Figure 2), which is — 



most truh- — a Traveller's Joy. 



Each tiny part of one of these 



clusters consists of a tinv fruit, 



called an achene, bearing a verw 



\ery slender, silky, hair\- appendage, 



which is so light that the slightest 



puff of wind catching it when the 



fruit is ripe, enables the latter to 

 be wafted away through the air 

 like a bit of gossamer. Another 

 lovely example mav be seen in the 

 i^vass Stripa pen iiata (see Figure 1), 

 one that is often grown in gardens 

 for decorative purposes. The fruit 

 of this plant is an elongated, very 

 sharp. needle - pointed achene, 

 cox'ered with short, soft, silk\- hairs, 

 which are reflexed : from its upper 

 end s[>rings a slender, string-like 

 stem that becomes cork-screwed for 

 part of its length and then straight : 

 above this portion rises a verv long 

 (often more than a foot in length) 

 delicate hair\' awn. In its own 

 nati\e haunts abroad these awns 



Figure 2. 



.\wned achene of 



Traveller's Joy. 



Clematis vitalba 



(life size). 



Figure 3. 



Awned achene of 



Water .A v e n s , 



Gcitni paliistris 



(enlarged). 



Figure 4. 



Tip of liaiiy awn of Geutn pcilnstris 

 (greatly enlarged). 



Figure 5. 



Base of the hairy awn of Gciiin piilitsfris 

 (greatly enlarged). 



467 



