416 STARCHES OF LEGUMINOS^, 



In gross general appearances the starches of Vicia, Phaseolris, Lens, and Lathjrus do not differ 

 materially, but those of Mucuna, DoUchos, Pisum, Arachis, and Wistaria exhibit more or less dis- 

 tinctive peculiarities; and in the case of Pisum, Arachis, and Wistaria certain decided individualities. 

 Comparing the photographs, the departure of the grains of these genera from those of the Vicia- 

 Phaseolus type is especially noticeable in the marked tendency to smoothness of outline and to 

 roundness; to the less conspicuous fissuration, especially as regards the longitudinal fissiue; and to 

 the more evident lamellation. Very much the same differences appear in DoUchos. 



The starches of Pisum are, as stated under that head, divided into two very different groups, 

 those of the wrinkled peas being of the rosette type, and those of the round and indent peas being 

 of the bean type or Vida-Phaseolus type. The starch of Wistaria, while having general resemblances 

 in shape to the Vicia-Phaseolus type, is conspicuously lacking in the marked fissuration so dis- 

 tinct in the latter, and the grains are only from a fourth to a third as large. In Arachis a type 

 is observed entirely different from those noted in the other Leguminosce. From the foregoing it is 

 obvious that there is no single type of grain characteristic of this family, and that to speak of a 

 leguminous type of grain is absolutely vague and misleading. 



In polariscopic, color, temperature, and chemical reactions the different genera show specific 

 peculiarities. It will be observed that there is throughout the members of the family a common 

 type of reaction-curve, and that each genus is characterized by peculiar modifications of this curve. 

 Striking variations will be noted in the case of each of the agents employed. Thus, in the degree 

 of polarization, it is high to very high in Lens, high in Vicia, a trifle lower in Phaseolus and Arachis, 

 below fair to fairly high in Lathyrus and also in the second group of Pisum and in Wistaria, fair in 

 DoUchos, and low in the first group of Pisum, and so on, with the other records. It is of interest to 

 note that the histological departures recorded in the starches of Arachis and Wistaria are accom- 

 panied by corresponding departures in the reaction curves. It is probable, considering the wide 

 range of botanical peculiarities observed in the Leguminosce, that a large varietj' of histological 

 types of starches will be found which will show related peculiarities in their physical, physico- 

 chemical, and chemical properties. 



