74 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



less in a good many orders the seeds appear to 

 depend for dispersion on their minuteness and 

 abundance, and show no further specialisation. 

 Small seeds of this description occur in Scrophula- 

 riacece, CrassulacecB, Cistacece, Campanulacece, Lyth- 

 racece, Orobanchacece, BegoniacecB, and in many 

 Caryophyllacece, Gentianacece, Saxifragacece, Papave- 

 racece, etc. Fruits or mericarps, adapted by their 

 small size to wind-dispersion, are exemplified in 

 Urtica; in some of the Malvacece and Labiatce; in 

 such Umhelliferce as Apium, JBupleurum, Ammi, Pim- 

 pinella, etc.; and in a few composites, such as 

 Artemisia, Bellis, Matricaria, etc. 



The longer the time during which the wind is 

 allowed to act upon a falling seed, and the larger 

 the surface upon which it acts, the farther will the 

 seed be carried. On this account, a reduction of 

 specific gravity is of greater importance than even 

 a reduced size. On this principle may be explained 

 the seed of Orchis, where the solid body of the seed 

 is loosely enveloped in the enlarged and membranous 

 integument. Such, no doubt, is also the advantage 

 conferred by the lax testa on the seeds of Pyrola, 

 Monotropa, Parnassia, Drosera, Nepenthes, etc. 



Compressed, flattened, and peltate seeds have their 

 shapes adjusted to meet these requirements. This 

 adaptation of shape is illustrated in the seeds of 

 Glaux, Trientalis, Anagallis, Iris, Gladiolus, Fritillaria, 

 Tulipa, Strychnos Nux-vomica, etc. 



A further advance in this direction is shown by 

 flattened seeds provided with a membranoiis border. 

 As examples of these margined seeds, which are 

 very common, may be mentioned Jihinanthus, 

 Lysimachia, Linaria, Spergula, Spergularia, Alyssum, 

 Idlium, Scilla, Syringa, etc. 



An improvement upon the membranous border is 

 made in the winged seeds of Casuarina, Bignonia, 

 Moringa, Swietenia Mahogani, etc. In the winged 

 seeds of Pinus, however, the wing is not derived 

 from the seed itself, but is a lamella from the cone- 



