APPENDIX A 



615 



bearing numerous flowers in a compact cymose group, with chaffy bracts. 

 The flower is constructed of : 



Perianth, segments 3+3, polyphyllous, inferior, dry and chaffy. 



Androecium, stamens 3 + 3, free hypogynous. 



Gynoecium, carpels 3, syncarpous, superior, with three long feathery 

 stigmas, united below into a short style. Ovary trilocular, with one ovule 

 in each loculus (Fig. 461, b, c). 



Fruit, a capsule dehiscent loculicidally. Seed with starchy endosperm. 



Pollination. The flower is strongly protogynous ; the feathery stigmas 

 project, while the perianth is still closed over the unopened stamens. Later 

 the stigmas wither, the perianth expands, and the anthers burst, setting 

 free the dry dusty pollen, which is readily shaken out, and carried away by 

 the breeze. There is no honey-secretion, or other attraction for insects, 

 but cross pollination is almost certain by the agency of wind. Self-pollina- 

 tion is prevented by the marked protogyny. Nevertheless fruit is almost 

 uniformly produced. 



The chief genus is Juncus, to which the Rushes belong. They are mostly 

 plants of moist habit, and of little feeding value for stock. Their presence 

 in grass-land is an indication of the need for draining. 



atr. O 



Family : Cyperaceae. Examples : Cotton-Grass, Sedge. 



(9) The Cotton-Grass (Eriophorutn vaginatum, L.) is a tufted perennial 

 herb of swampy moorlands, marked by its single cottony heads when in fruit. 



The flowering head rises about a foot from 

 the root-stock, and is composed of a single 

 spikelet of flowers in the axils of glume- 

 like bracts. Each hermaphrodite flower 

 is constructed as follows : 



Perianth, inferior, represented by 

 numerous bristles, which are developed 

 relatively late, and mature into the 

 " cotton " of the fruit. 



Androecium, stamens three, hypogynous, 

 representing those of the inner whorl. 



Gynoecium, carpels three, syncarpous, 

 and superior, with three stigmas. The 

 ovary is unilocular, with a solitary ovule 

 (Fig. 462). 



Pollination is effected by the wind, which 

 also carries out the transfer of the fruit. 



Fruit, a trigonous nut, with the cottony 

 tuft of the persistent perianth attached 

 at its base. The floral structure suggests 

 a modification of the Liliaceous type, by 

 cottony development of the perianth, loss of the three outer stamens, and 

 reduction of the ovary to a single loculus with one ovule. 



(10) For the structure of a Sedge, any of the following species of Car ex will 

 serve (C. glauca, Murr ; pallescens, L. ; pendula, Huds. ; hirta, L. ; flava, L. ; 

 or binervis, Sm.). The Sedges are perennial herbs of swampy ground, which 



A, floral diagram of a male flower of 

 Carex ; B, of a female flower with three 

 stigmas ; C, of a female flower with two 

 stigmas. D, diagram of female flower of 

 Carex. E, diagram of the hermaphrodite 

 spikelet of Elvna : a, secondary axis ; utr. 

 utricle or bract of secondary axis. (After 

 Eichler.) (Strasburger.) 



