54 RENNERT: SEEDS AND SEEDLINGS OF ARISAEMA 
hypocotyl. This type of germination does not seem to be due to 
a diseased condition of the seed or embryo or to an unfavorable 
environment nor does it appear to be advantageous to the young 
seedling. It might be suggested therefore that it is an expression 
of an inherent tendency in aroids to carry the young plantlet as 
far as possible in its development before an assimilatory organ is 
produced. If this conclusion be correct we have in A, Dracontium 
a transition stage between a seedling forming its corm outside of 
the seed coats with the aid of a plumule as in A. “riphyllum and a 
corm formation within the seed coats at the expense of the endo- 
sperm as is the case with Spathyema foetidus. 
Explanation of Plate 3 
Fic. 1. Seedling of A, Dracontium showing hypocotyl just emerging from seed. 
Fic. 2. Seedling of A. Dracontium. Hypocotyl has begun to enlarge, short root 
has appeared. 
Fic. 3. Seedling of 4. Dracontium, Root has elongated, root hairs have arisen. 
Fic, 4. Seedling of 4. Dracontium. Uypocotyl has enlarged greatly, first root 
has elongated, second root is just appearing. 
Fic. 5. Seedling of A. Dracontium. Wypocotyl has attained full size of first 
year’s corm, 
Fic. 6. Seedling of 4. Dracontium. Specimen in which the root system has been 
only slightly developed. 
Fic, 7. First-year corm of A. Dracontium. Formation of periderm at base of 
cotyledon has separated corm from seed. 
Fic. 8. Seedling of A. Dracontium which has produced plumule. 
Fic. 9. Seedling of A. Dracontium. More advanced ; note single contractile root, 
developed only in those cases where plumule is sent up. 
Fics 10, 11, 12. Variations in form of plumule in those seedlings of 4. D7a-_ 
contium which send up a leaf. 
Fics. 13, 14. Second-year leaves of 4. Dracontium when a plumule had been 
developed by seedling. 
Fics. 15, 16, 17, 18, 19. First leaves produced by A. Dracontium corms which 
have been developed without the aid of a plumule. 
Fic. 20, Seedling of 4. ¢riphyllum. Hypocotyl just emerging. 
Fic, 21. Seedling of 4. ¢riphyllum. Cotyledon lengthened, hypocotyl has begu® 
to enlarge, root has arisen. 
Fic. 22, Seedling of 4. ¢riphyllum. Second root appearing. 
Fic. 23. Seedling of A. ¢riphyllem. Second root has increased in length. 
Fic. 24. Seedling of 4. /riphyl/umu. Plumule has emerged from cotyledonary 
sheath. 
Fic. 25. Seedling of 4. ¢rifhyllum. Petiole of plumule has lengthened, a third 
root has appeared. Hypocotyl perceptibly enlarged. 
Fic. 26. Seedling of A. ¢riphyllum. Contractile root formed, plumule fully e*- 
panded. 
Fic. 27. Seedling of A. kyérida._ Plumule produced. 
Fics. 28, 29, 30. Variations in form of leaf produced second year by A. Aydrida- 
