207 



CuscuTA Americana L. 



Stanley Coulter. 



In a study of the genus Cuscuta a peculiar situation in regard to 

 Cuscuta Americana L. arose, wliicli may prove of interest. The history 

 of this species seems evident. The original plant vs'as collected by Sir 

 Hans Sloane in Jamaica and is described in Hist. Jamaica, 1707, vol. 1, 

 p. 201. Gronovius in 1743 determined a specimen collected by John Clay- 

 ton to be the same as the Sloane plant, to Avhich he definitely referred; 

 PlantfB Vlrginica, p. 18: 1743. Linnteiis, 1753, in Sp. PL, vol. 1, p. 124, 

 copies the description of Gronovius verbatim and gives the form its bi- 

 nomial name. Linnseus refers specifically to PI. Virg., p. 18. 



It is clear, then, that Sloane's plant in the South Kensington Museum 

 should stand as the type of Cuscuta Americana L. That as a matter of 

 fact our present Cuscuta Americana L. is a very different plant from that 

 of Sir Hans Sloane will perhaps be clear from the discussion which fol- 

 lows. Indeed, Cuscuta Americana L. as at present understood seems to 

 have arisen without a type upon which to rest. 



Through the courtesy of the authorities of the South Kensington 

 Museum I was enabled to study the Sloane plant somewhat carefully, 

 with the following results: 



Calyx gamosepalous; tube short; lobes coriaceous in center, mem- 

 branous at edges; diverging at an acute angle; apex abruptly acute; large 

 cells (plainly made out with hand lens) irregularly scattered; membranous 

 part of lobes, as well as inner and outer surface of petals, thinly clothed 

 with velvety trichomes. Lobes of calj'x one-half longer than the tube, 

 the tips meeting those of the reflexed lobes of the corolla. Lobes rather 

 spreading, at least not closely appressed to tube of the corolla. 



Corolla; tube urceolate. about 2 mm. long; lobes reflexed, obtuse, sep- 

 arating from each other by a narrowly acute angle, about one-half as long 

 as the tube. In many cases margins of petals infolded, which, however, 

 may be due to imperfect di'ying. 



Stamens apparently four, aboiit one-half as long as lobes of the corolla, 

 though exserted on account of the reflexi-^l habit of the lobes. 



Styles as long as tube of corolla, widely diverging. 



Stigmas decidedly globose-capitate. 



