530 ROBINSON. 
Nicolson referred is clearly shown by the expression “sub Jalapiae 
nomine.” Of this plant Plukenet gives a figure cited by Ray and 
doubtless in the opinion of Ray representing his plant. This figure 
shows a highly conventionalized twiner with alternate deltoid-ovate 
entire leaves and solitary short-peduncled axillary flowers. The flow- 
ers show no corolla but merely a small calyx with relatively short lobes 
which do not equal the tube. It is impossible to regard this figure 
as representing I. cathartica Poir. which is characterized by calyx- 
lobes of unusual length, greatly exceeding the short tube. The 
writer after some search has failed to find that Linnaeus expressed 
any opinion in regard to the identity of this particular figure of 
Plukenet, and from its general lack of detail it would probably be 
impossible to place it with any certainty. 
It may be seen from the data here assembled 1) that Nicolson made 
no Convolvulus africanus, a name which seems to have arisen from a 
clerical error of Choisy. 2) that Nicolson in employing the name 
Convolvulus americanus had no thought of coining a new designation 
or describing a new species, but was merely applying — in all proba- 
bility erroneously — the pre-Linnaean Convolvulus Americanus of 
Ray to a purgative twiner of Santo Domingo. He gives no botanical 
characterization sufficient to give validity to the name and merely 
discusses briefly the pharmaceutical properties. Nicolson’s type 1s 
not known and even if the plant he was treating could be ascertained 
it is doubtful if the botanical type of Convolvulus americanus would 
not have to be sought in the plant of Ray, whose name Nicolson was 
intending to apply, rather than the plant to which he perhaps mis- 
takenly applied it. As we have seen, the plant of Ray may be traced 
back to a figure of Plukenet’s which cannot be I. CATHARTICA Poir., 
a well known name that thus relieved of an earlier synonym retains 
its validity. : 
Ipomoea crassicaulis (Benth.), comb. nov. Batatas ? crassi- 
caulis Benth. Voy. Sulph. 134 (1844). Ipomoea fistulosa Mart. ex 
Choisy in DC. Prod. ix. 349 (1845). I. texana Coult. Contrib. U. 5. 
Nat. Herb. i. 45 (1890). 
OPERCULINA ORNITHOPODA (Robinson) House, var. megacarpa 
(Brandegee), comb. nov. Ipomoea sp. Rose, Contrib. U. S. Nat. 
Herb. i. 344 (1895). JI. megacarpa Brandegee, Zoe, v. 218 (1905). 
Operculina Roseana House, Bull. Torr. Bot. Club, xxxiii. 500 (1906) , 
Bot. Gaz. xliii. 414 (1907). Formae typicae floribus fructu ete. simil- 
lima differt foli g ti Ito latioribus(0.9-3.5 cm. latitudine). 
The writer agrees with Mr. House that this plant, differing in range 
