50 Rennert : Seeds and Seedlings of Arisaema 



the individual leaflets. In some, the side leaflets may be narrowly- 

 lanceolate while others may approach an elliptical shape. The 

 mid leaflet is generally broader than the lateral ones, but here too 

 a variety of forms may occur. At the end of the second season's 

 growth there is still a slight diflerence in the size of the corms of 

 those plants of A. Dracontuun which have borne a plumule the first 

 year and those that have not. The root systems are, however, simi- 

 lar; six adventitious roots are developed in each. Except in the 

 retarded development of its plumule, the development of the stem- 

 bud of A. Dracontiinn agrees with that shown by A. tripJiylluui. 

 The repression of the plumule does not seem to be correlated with 

 any variations in the stem-bud of the second season, since varia- 

 tions of leaf form occur as frequently in second-year plants which 

 produced a functional plumule the first season. 



The principal differences between the seedlings of A. Dracon- 

 tiiivi and A. tripJiylluin consist not only in the reduction and vari- 

 ability of the roots, the variation and repression of the plumule on 

 the part of ^. Dracontiiini, but also in the precocious enlargement 

 of the corm. This difference arises as soon as germination starts ; 

 in A. Draco)itiwn the foodstuff of the endosperm is employed 

 directly to build up the hypocotyl at the expense of the devel- 

 opment of root and plumule. In A. inphyHuJii, however, as 

 soon as the hypocotyl breaks through the seed coats, the roots 

 are sent out and attain some development at once, the plumule 

 then appears, and in normal cases it is only after this assimilatory 

 organ is well established and the seedling has separated from the 

 seed that the hypocotyl begins to enlarge. In A. triphylhini the 

 endosperm furnishes the material which is necessary to bring the 

 root and plumule to an advanced stage of development, and the 

 food material for the hypocotyl is supplied by the assimilation of 

 the plumule. The early enlargement of the corm and the repres- 

 sion of the plumule can scarcely be held to be due to a patholog- 

 ical condition of the seed or to an unfavorable environment, as the 

 seeds planted were perfectly sound and the plumules in the em- 

 bryos of those from the same lot which were examined showed no 

 evidence of the attacks of parasites or any abnormality, while the 

 conditions under which the plants were grown corresponded to the 

 normal environment of these plants as was well demonstrated by 



