1900 ] PERENNIAL HERBS 187 
middle of September gives rise to new roots, while its terminal 
bud, having stopped its growth, remains quiescent until next 
spring. At the middle of November, when the aerial shoot has 
died down, the runner begins to decay from its base, while the 
roots have reached a length of about 20™ and are still growing. 
During winter the runner decays, only its end portion with the 
roots remaining alive, and the plant assumes again the form in 
which we find it in the spring. 
LINCOLN, NEBRASKA. 
BIBLIOGRAPHY. 
De Vrizs, H. Ueber die Kontraction der Wurzeln. Landwirtschaftl. 
Jahrbiicher 6: 927. 1877; 8: 474. 1879; 9: 37. 1880 
WarminG, Euc. Om Skudbygning, Overvintring og Foryngelse. Natur- 
hist. Forenings Festskr. Kjébenhavn 188 
eber perenne Gewdchse. (Botan. Centralblatt. 18: —. 1884.) 
ForRsTe, AuG. F. The development of Symplocarpus foetidus (L.) Salisb. 
Bull, Torrey Bot. Club 15: 154. 1888. 
Fost, L. Die Zerkliiftungen einiger Rhizome und Wurzeln, _ Bot. Zeitung 
48: —. 1890. 
ARESCHOUG, F. W. C. Beitrage zur Biologie der geophilen Pflanzen. Acta 
Reg. Soc. Phys. 6: —. 1806. 
RImBacu, A. Ueber die Lebensweise des Arum maculatum. Berichte d. 
Deutsch. Bot. Ges. 15: 178. 1897. 
Lebensverhaltnisse des Altium ursinum. Ibid. 15.248. 1897. 
oe Beobachtungen an Colchicum autumnale. Ibid. 15: 298. 
97- 
Die kontractilen Wurzeln und ihre Thitigkeit. Beitrige zur wissen- 
Schaftl, Botanik. 2: 1, 1897. 
Das Tiefenwachstum der Rhizome. /did. 3:177. 1898. 
a Lilium Martagon. Berichte d. Deutsch. Bot. Ges. 16: 104. 
I . 
Beitrage zur Physiologie der Wurzeln. did. 17: 18. 1899. 
EXPLANATION OF PLATE XIII. 
oo ie drawn from nature, and, with exception of fig. 70, are 
Fig, ; j S gist horizontal dash-lines indicate the surface of the ete - 
Seed ; Meer ts of Arisaema Dracontium still in connection wit 
Fig, 2 a. cotyledon ; Z, first leaf : yr, first root. — 
developed a v€ same, near the end of the first period of growth, having 
Its roots; 7, tuber ; ~', contractile adventitious roots. 
