ADAPTATIONS OF STRAND PLANTS FOR DISSEMINATING SEEDS. 393 



Succulency of subaerial organs was the only kind of water-storage 

 apparatus detected in this vegetation. 



Owing to the possession of various protections against excessive 

 loss of water, most strand plants are very slow to wilt when detached 

 from the soil. 



PROTECTION AGAINST EXCESSIVE LIGHT, 



Several of the modifications described as protecting against too 

 great transpiration are perhaps equally valuable to the plant by pre- 

 venting the injurious action of too strong and long-continued light. 

 In the present state of our knowledge, however, it is often not possi- 

 ble to distinguish between the operation of these two factors and the 

 resulting modifications of the organism. 



The development of thorn-like brandies (as in Prunus angustifolia)\ 

 of prickles (Smila.r spp., Rubus spp., Aralia spinosa, Zanthoxylum 

 clava-her cults); of spines ( Opuntia opuntia and the leaf tips of Yucca 

 filamentosa) is in all probability a consequence of the physical con- 

 ditions (great heat and strong light) which render necessary protec- 

 tion against excessive loss of water. It is hardly conceivable, how- 

 ever, that these structures are themselves of any use to the plant as a 

 protection against such conditions. Prickly and thorny plants are 

 most abundant on the inner slope of the fixed dunes and in the woods 

 behind them, where the heat is more intense and the soil is drier than 

 anywhere else in the Dismal Swamp region. 



POLLINATION. 



No important observations were made in regard to the pollination 

 of the flowers of strand plants. Anemophilous fecundation, however, 

 undoubtedly predominates. The species which can safely be referred 

 to one or the other method of pollination are as follows: 



Anemophilous: All Gramincae, Cyperaceae, .Juncaceae, Myrica, Qnercus, Cheno- 

 podium. Iva inibricata, Xanthium. 



Self -fertilizing: Lechea maritima. 



Entomophilous: Oenothera humifusa, Monarda punctata, Gelsemium sempervi- 

 rens, Tecoma radicanx, Lonicera sempervirens. 



DISSEMINATION OF SEEDS. 



Structures, especially developed in or about the fruits, which are 

 useful to the plant in the dissemination of its seeds occur in many of 

 the strand plants, although they are doubtless in most cases a heritage 

 from inland ancestors rather than modifications acquired after resi- 

 dence upon the strand. The majority of these are adaptations to 

 transportation by the wind, although other methods are not lacking. 

 The various structures may be classified as follows: 



(1) Adaptations to wind transportation. 



(a) Specific gravity small in proportion to size, as in the spike- 

 lets of Gramineae (Spartina patens, Uniola paniculata, Arnmophila 



