866 



THE DISPERSION OP SPECIES BY MEANS OF FRUITS AND SEEDS. 



(e.g. nilandsia; see fig. 475 ^) only one pole of the seed is furnished with a tuft of 

 hairs, whilst in Adenium (see fig. 471 ^), belonging to the family Apocynacese, both 

 poles are so provided. In Valerianacese (e.g. Valeriana; see fig. 4713) ^nd i^ 

 Composite (e.g. Seriecio and Taraxacvm; see figs. 471 1.^'^) the tuft of hairs which 

 acts as a parachute springs from the upper extremity of the achene. Sometimes 

 the parachute and the body it keeps in suspension are connected by a slender stalk 

 (e.g. in TiUandsia and Taraxacum); but usually the former is directly sessile on 

 one extremity of the seed or indehiscent fruit as the case may be. In VeHicordia 

 (see figs. 469 «• ''■ ^), of the family Myrtacese, a strange and beautiful parachute is 

 formed by five petals which are in the form of little fans, each composed of ten 



Fig. 470. — Dispersiori of fniits and seeds by the ■wind. 

 Bombax. s Anemone sylmstris. » Qossypium Barbadense. 



feather-like lobes, and in some Labiatse, as, for instance, Micromeria nervosa (see 

 fig. 471 '), the radiating, hair-studded segments of the fruiting calyx constitute a 

 similar apparatus. On the other hand, in several other Labiates (e.g. BaUota 

 acetabulosa), in many Plumbaginacese (e.g. Armeria; see fig. 468 *), and in several 

 Dipsacese (e.g. Scabiosa; see fig. 468^) the parachute is developed from the dehcate, 

 dry membranous calyx or from the epicalyx. Nor must reference to the Cape 

 Silver Tree (Leuoadendron argenteum, one of the Proteacese) be omitted. The 

 fruits here are produced in large cones not unlike those of the Stone Pine {Pinus 

 Pvnea) in form and dimensions. Each bract of the ripe cone subtends a fruit 

 consisting of a nut with persistent wiry style and stigma. The 4-lobed perianth 

 also persists as a membranous parachute, its originally free apices haAring become 

 connate above the nut and around the style. Ultimately the original attachment of 

 the perianth below the ovary becomes dissolved, and as the nut falls out of the cone 



