344 FIELD AND WOODLAND PLANTS 



of the swellings gives rise to suckei's that penetrate into the tissues 

 of the latter, and withdraw the organic food necessary for the 

 continued existence of the plant. 



The Dodder now grows rapidly, giving off branches which search 

 in all directions for additional supports, sometimes cUmbing from 

 one plant to another, and producing new suckers whenever a 

 favom-able situation has been reached. The plant has now all it 

 requires both in the way of mechanical support and nourishment, 

 and its lower part, thus rendered useless, soon withers, breaking 

 all connexion with the soil on wliich the seed originally germinated. 

 New branches continue to form, each one producing additional 

 suckers for the extraction of food from the host or hosts, until a 

 tangled mass of clinging stems is the result. Then the globular 

 clusters of little flowers appear, followed by balls of small capsules 

 which throw off their lids when ripe, allowing the seeds to be shaken 

 out by the wind. The Dodder plant now withers, leaving, in the 

 autumn, its dead tangles of chmbing filaments still attached to the 

 withered herbs on ■«'liich it fed, or to the branches of the tree which 

 served as its host. 



Other parasitic plants possessing no chlorophyll, and therefore 

 incapable of building up organic compounds for themselves, derive 

 their food from the roots of trees and shrubs. 



Among these is the Toothwort {Lathnva), -which is carnivorous 

 as well as parasitic, and is described in om- chapter (XXIV) deahng 

 with carnivorous plants, so that we need only refer here to its 

 habit as a parasite. 



The seed of this plant germinates on the damp ground to wliich 

 it falls in early summer. The young root penetrates into the soil, 

 deriving its nourishment entirely from the food reserve that was 

 stored up in the seed, and soon sends out lateral branches in search 

 of the roots of a suitable host. If it fails to attain tliis end by the 

 time that the reserve is exhausted, it dies ; but if it succeeds in 

 reaching tlie root of an Elm, Hazel, Hornbeam, Ash, Pojilar, or other 

 tree, it fastens itself to it, and develops suckers wliicli penetrate 

 into the substance of the root to extract its sap. The parasite now 

 grows very rapidly, producing its underground stems, with their 

 fleshy, overlapping scales, as described on p. .352. 



The Broomrapes of the same order {Orobanchacece) are very 

 similar in their parasitic habits to the Toothwort, and, hke the latter, 

 they possess no chlorophyll. The seeds germinate on the damp 

 soil, producing a long, narrow embryo that grows downward into 



