132 Trans. Acad. Sci. of St. Louis. 



logical characters. Louis Petit* has published an important 

 monograph (422) on the anatomical characters of the petioles 

 of various orders including representative tribes of the order 

 Jjeguminosae. 



Pritzel (428) has recently published a paper of considerable 

 length on anatomical characters, especially in the endosperm 

 of Parietales. According to Pritzel the arrangement of the 

 Parietales is an unnatural one. The Chlaenaceae are ex- 

 cluded. Pritzel finds that their anatomical characters show 

 them to be allies of the Malvaceae and not Theaceae, where 

 the order was placed by Engler and Prantl in their Natiir- 

 lichen Pflanzenfamilien. 



If differential points of this kind occur in related species, 

 what of hybrids ? It has been shown that hybrids show inter- 

 mediate characters. Wettstein (469) has found excellent 

 characters in the hybrids of some conifers, Pinus and Juni- 

 perus. He determined that J. Kanitzii had its origin in 

 J. sabinoides X J. communis. The anatomical structure con- 

 firmed his previous opinion. t Intermediate anatomical char- 

 acters also occur in Pyrus Malus X P. ioringo. If these 

 characters occur and repeat themselves in the hybrid offspring 

 it would certainly seem probable that anatomy should often 

 show some most tangible characters. 



This investigation as applied to seeds reveals many excellent 

 characters, shown to better advantage by Harz (99, 2 : 555- 

 1350) than by any other writer. Godfrin (71) was most con- 

 servative in expressing the opinion that anatomical seed char- 

 acters could not be or are of but little value for systematic 

 purposes. I expressed a conservative view in a paper on the 

 structure of the testa in Euphorbiaceae (416), to which Gram 

 (339. 340) takes exception. I recognized differences, and 



* The author has a good bibliography and refers to the work of Trecul on 

 the same order, and Acqua, whose work is said to agree with Petit. Mc- 

 Alpine and Renfrey (402) made a careful study of the Eucalyptus petiole, in 

 which they found valuable characters. In a later work, 1889, Petit (Nou- 

 vellesrecherches sur le petiole des phanerogames. Acts. Soc. Linneenne de 

 Bordeaux 1889. Separate, 50, pi. 1-4), discusses additional species, 

 Including several more Leguminosae. 



t The Wettstein paper gives some of the literature. Other cases are 

 cited by Kerner-Oliver, Natural History of Plants. 



