628 



SCIENCE 



[N. S. Vol. XLVI. No. 1200 



One of the present necessities is to collect 

 the cultivated plants in their different 

 forms from many localities, and repre- 

 senting the stocks of different dealers, in 

 precisely the same spirit in which feral 

 plants are taken for herbaria. "Without 

 such sources of information, we can neither 

 understand the systematology of the plants 

 themselves or bring the best aid to the stu- 

 dent of heredity. 



[The speaker here mentioned the lack of 

 record material in studies of the systema- 

 tology of Coleus and other groups ; and ex- 

 plained also the unsatisfactory practise on 

 which descrip)tions of large numbers of cul- 

 tivated species still must rest.] 



Excellent illustration of the confusion in 

 cultivated plants, even of relatively recent 

 introduction, is afforded by the velvet- 

 beans now grown in the southernmost states. 

 These plants have been referred indiscrim- 

 inately to Mucima pruriens, long cultivated 

 in the tropics. On careful recent study, 

 however, the American planted material is 

 found to be so different from Mucuna as 

 to necessitate generic separation, and the 

 genus Stizoloiimn has been revived to re- 

 ceive it. The common cultivated velvet- 

 bean is found by Bort to be an undescribed 

 species, probably of oriental origin, and it 

 has been named and described Stizolohium 

 Deeringianum. Subsequently other species 

 have been newly described in the cultivated 

 stocks. One need not go far for many 

 comparable illustrations of the confusion 

 in which cultivated plants have lain. 

 Americans are now specially active in re- 

 solving these complexities. As a running 

 random comment may be cited the work of 

 Rose in the cacti, Swingle in Citrus, Rehder 

 in Wisteria, oriental Pyrus and others, 

 "Wilson in Japanese cherries, Safford in 

 Annonacese. It is not too much to say that 

 any of the important groups of cultivated 



plants will fall to pieces as soon as touched 

 by the competent modern systematist. 



The systematist who works in these do- 

 mesticated groups must first make large 

 collections of new information and mate- 

 rial. It is becoming a habit with him to 

 travel extensively to study the plants in 

 their original countries, and to bring his- 

 tory and ethnography to bear on the prob- 

 lem. He is not content until he arrives at 

 sources. 



[The speaker discussed, and illustrated 

 with herbarium material, the recent studies 

 in the cultivated poplars, whereby the sub- 

 ject has been opened for discriminating in- 

 vestigation.] 



Nor does the confusion lie only with 

 plants of ancient domestication or with 

 those native to countries which have not 

 yet been well explored. The horticultural 

 blackberries have been brought into culti- 

 vation from American wild stocks within 

 seventy-five years or less, they have been 

 accorded careful study by several special- 

 ists, yet no one is ready to name the spe- 

 cies from which the different forms have 

 come. A number of systematists are work- 

 ing on them, and yet they are in need of 

 further study, both in the wild and in culti- 

 vation. In Primus is a comparable ease, 

 horticultural forms in many named vari- 

 eties of native plums having come into cul- 

 tivation within fifty years. It fell to my 

 hand to attempt the first critical taxonomic 

 writing of these native plants, in 1892 ; but 

 in 1915 "Wight completely recast the treat- 

 ment, in the light of accumulated experi- 

 ence. This illustrates my earlier remark 

 that every group should be newly mono- 

 graphed at frequent intervals. 



Perhaps we do not sufficiently realize 

 the great numbers of species of plants now 

 in cultivation. "We may have in mind the 

 247 species studied by DeCandolle in his 



