11 1902 



NORMAL AND TERATOLOGICAL THORNS OF 

 GLEDITSCHIA TRIACANTHOS, L.* 



J. Arthur Harris. 



In Gleditschia, a genus of wide distribution,! including ten 

 or more species, X abnormalities of structure are of very fre- 

 quent occurrence. Fasciation has been observed in the twig, 

 malformations in the leaves have been noted by many writers. 

 Synanthy is often observed. The occurrence of two carpels 

 in otherwise single flowers is very common. Either of these 

 cases may lead to the formation of double fruits. Deviations 

 from the normal structure are of frequent occurrence in the 

 seedlings. The seeds sometimes contain more than one em- 

 bryo and the plants developing from them may be grown 

 together. The occurrence of three cotyledons, splitting of 

 the cotyledons, and the growing together of the same, either 

 laterally or dorsally, have been observed. 



The above anomalies are mentioned by Penzig,§ where def- 

 ences to the literature, as well as a somewhat more extensive 

 mention of the different cases, may be found, for G. triacan- 

 thos. Some of the same deformities are noted for other 

 species of the genus and some teratological phenomena not as 

 yet observed for G. triacanthos are noted for other species. 



* Presented in abstract to The Academy of Science of St. Louis, Decem- 

 ber 2, 1901. 



f Gleditschia is found in Eastern North America and in the mountains of 

 West Tropical Africa. It is represented by one species in Northern Persia 

 and the Province of Talysh, south of the Caspian sea. It is widely dis- 

 tributed iu Japan and China. In the Tertiary Period it existed in Europe. 

 G. amorphoides has recently been described from South America. — See 

 Sargent, C. S. Silva of North America. 3 : 73-80. 1892. — Taubert, P. Zur 

 Kentniss einiger Leguminosen-Gattungen. Ber. D. B. G. 10: 637-642. 1892. 



I Index Kexoensis gives eight. At least two have been since described 

 and the Gleditschia-; of some regions, as China, are very imperfectly 

 known. — See Sargent, I. c. 



§ Peuzig, O. Pflauzen-Teratologie. 1:404-407.1890. 



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