500 BOTANY OF THE LIVING PLANT 



The Fruit matures as a dry capsule, splitting by six longitudinal slits into 

 three larger and three smaller strips, which remain united at their ends. 

 The minute seeds are scattered by the wind. 



Pollination. The flower being resupinate, the large posterior labellum pro- 

 jects forward as a convenient platform for the visiting insect, while the entry 

 to the spur is presented directly to his proboscis just below the column. 

 But the passage is obstructed by the rostellum. On inserting his proboscis 

 this is pushed aside. As it breaks away it lays bare two sticky discs, which 

 adhere to his proboscis, their cement setting firmly in the few seconds during 

 which he is engaged in probing the honey-containing tissue at the base of the 

 spur. On his withdrawing it, the coherent contents of the two anther-lobes 

 are themselves withdrawn, and appear as club-shaped pollinia, fixed by their 

 sticky discs in an erect position. But in a few seconds this position changes, 

 and they curve strongly forwards (Fig. 402, v. vi.). Meanwhile, if he has flown 

 to another flower, they are in such a position that as he inserts his proboscis, 

 they will impinge directly on its stigma, which is below the rostellum. The 

 pollen, which is in coherent masses, is then held by the sticky stigma. Thus 

 cross-pollination is effected with a high degree of certainty, while self-pollina- 

 tion is mechanically impossible. The efficiency of the mechanism is shown 

 by the constancy with which the Spotted Orchis sets its fruit as it grows in 

 the open. This is only one of the very various methods of pollination seen 

 in this wonderful family. For further details reference may be made to 

 Darwin's Fertilisation of Orchids. 



ORDER: GLUMALES. 



The Cyperaceae and Gramineae, which are grouped under this heading, 

 have in common hypogynous flowers, more or less specialised in relation to 

 pollination by the wind, while their flowers are often grouped in dense in- 

 florescences. The Juncaceae may be associated with them as a Liliifloral type 

 only slightly modified. The construction of their flowers may be referred in 

 origin to the Liliaceous type, but the perianth is inconspicuous, and the 

 pentacyclic, usually trimerous structure is more or less reduced in the number 

 of the parts. The name Glumiflorae refers to the fact that the bracts are 

 usually stiff and dry, and are called Glumes or Paleae, which constitute the 

 " chaff " of Grasses. The gynoecium is superior, and though it may be tri- 

 locular with numerous ovules in the less specialised forms, in the more 

 advanced Sedges and Grasses it is unilocular, and contains only a single ovule. 

 The fruit then matures as a Grain, or Nut. The plants are mostly annual or 

 perennial herbs, frequently with long internodes. The alternate leaves are 

 sheathing below, with a simple grass-like blade, and often a ligule projecting 

 upwards at the junction of sheath and blade. 



Family : JUNCACEAE. Example : FIELD WOOD- RUSH. 



(8) The Field Wood-rush (Luzula campestris, Willd.) is a perennial very 

 common on poor grass-land.- It has a Grass-like habit, but its flowers are 

 constructed on the Lily-type. The root-stock produces leaves with sheath 

 and blade, but no ligule. The axis elongates upwards into an inflorescence 



