12 THE SOY BEAN ; HISTORY, VARIETIES, AND FIELD STUDIES. 



Harz (Zeitschrift ties Landw. Vereins Bayern, 1880, and Land- 

 wirtschafthliche Samenkunde Handbuch, 1885) p;ives an even more 

 elaborate classification than Martens of the varieties of Soja hispida, 

 dividing the species into two subspecies on the form of the pod, and 

 numerous varieties on the shape and color of the seeds, but it is not 

 apparent that he grew the plants. His grouping is as follows: 



Soja platycarpu Harz. Flat-podded soy beans. 



1. olivacea Harz. Seeds olive-brown. 



2. punctata Harz. Seeds olive, speckled with brown. 



3. melanospcrma Harz. Seeds black, elongate (Soja compressa nigra Martens). 



a. vulgaris. Hilura flat; seeds 9.1X5.5X3.5 mm. 



b. renisperma. Hilum concave; seeds 10. 1X5X3. 8-4 mm. 



c. nigra. (Soja elliptica nigra Martens. ) Seeds little compressed, 11X5.1 X 



4.4 mm. 



d. riibrocincta. Like the preceding, but dark red about the hilum. 



4. plalysperma Harz. Seeds black, flat. 



5. parvula Martens. Seeds black, small. 

 Soja tumida Harz. Swollen-podded soy beans. 



6. pallida Roxb. Seeds yellow or yellowish. 



7. castanea (Soja elliptica castanea Martens). Seeds brown. 



8. atrospervia Harz. {Soja sphaerica nigra and S. sphaerica minor Martens.) 



Seeds black. 



This classification differs from that of Martens primarily in recog- 

 nizing two main groups based on the shape of the pod rather than 

 three groups based on the form of the seed. 



While either the system of Martens or that of Ilarz wdll classify the 

 material, they are of little value either botanically or agronomically. 

 To accommodate the much larger number of varieties we have 

 studied, either scheme would need to be elaborated greatly. Further- 

 more, there are all possible intergrades between flat pods and tumid 

 pods, as also between oval, globose, and compressed seeds. Botan- 

 ically speaking, the form of the pod and the color and form of the 

 seeds is of little significance. Agronomically the habit and size of 

 the plants are much more important characters, and in many cases 

 varieties very different in these respects have closely similar seeds. 



VARIETAL CHARACTERISTICS OF SOY BEANS. 



The characters that distinguish soy-bean varieties may be con- 

 sidered under the following categories: 



HABIT OF GROWTH. 



All soy beans are strictly determinate as to growth; that is, the 

 plants reach a definite size according to environment and then mature 

 and die. The great majority of the varieties are erect and branching, 

 with a well-defined main stem. (Pis. II and III.) The branches may 

 all be short, or the lower ones elongated, either spreading or ascending. 



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