486 AMERICAN JOURNAL OF BOTANY [Vol. 10, 



II. Inflorescence always axillary. Stipe without disk at the 

 base. 

 Pod flat, when inflated at least the endocarp flat, 2-valved. e. Robiniinae. 

 Pod inflated or bladdery, rarely flat, then 2-celled lengthwise. 

 Style bearded above; pod inflated or bladdery, not 

 dehiscent or opening only at the apex, more rarely 2- 

 valved, never with a longitudinal partition. /. Coluteinae. 



Style naked, more rarely hairy like a brush around the 

 stigma; pod 2-celled or nearly 2-celled lengthwise, 

 seldom 1 -celled. g. Astragalinae. 



From this key it is evident that the subtribes are very artificial and that 

 it has been very hard to find really good distinctive characters. It is also 

 evident that these characters have been drawn without taking into con- 

 sideration the American genera in full, in which they break down repeatedly. 



While the strophiole is very well developed in the Brongniartiinae, in 

 fact better so than in any other group in the Fabaceae, strophioles are 

 present, although small, in several species of Cracca. 



The Tephrosieae of Bentham (Tephrosiinae of Taubert) is in itself 

 not a natural division, for Barbiera is not at all closely related to the rest, 

 being distinguished by the long-clawed petals, the presence of 2 bractlets 

 beneath the tubular calyx, and the style bearded along the upper side. In 

 fact, it has no close relative in the whole tribe. The paired bractlets are 

 found in Sesban and related genera and in Diphysa, which are all included 

 in the Robinieae of Bentham (Robiniinae of Taubert). 



Neither does Krauhnia seem to be closely related to Cracca or Galega, 

 but apparently forms a natural group with several Asiatic genera, especially 

 Millettia. 



The position of the inflorescence, being either terminal or apparently 

 opposite the leaves, a character very important in the minds of both Ben- 

 tham and Taubert, seems to be of little value, for in many species of Galega 

 and a few of Cracca (see explanation under Cracca) the inflorescence is 

 axillary, just as in the Coluteinae and Astragalinae. The other character, 

 the presence of the disk at the base of the staminal sheath, is also unreliable, 

 for, while it is fairly well developed in Cracca and Krauhnia and their 

 relatives, it is not at all in Barbiera. 



The Robinieae of Bentham (Robiniinae of Taubert) is distinguished 

 from the Coluteae and Astragaleae (Coluteinae and Astragalinae of Taubert) 

 by the one-celled, two-valved, flattened, not inflated pod, but in the genus 

 Diphysa, included in the first, the exocarp is strongly inflated, forming two 

 lateral elongate bladders, and in Homalobus and Kentrophyta, segregates 

 of Astragalus, the pod is decidedly compressed and fulfills all the characters 

 ascribed to the Robinieae. In Bentham and Hooker's Genera Plantarum 

 the following remarks are made: "In Astragalus paucis [legumenj planis- 

 simum est, sed membranaceum et perfecte septatum." This statement 

 applies to Hamosa Med., a segregate of Astragalus found both in the Old 



