PRIMARY CHARACTERS IN THE SPECIES OF RHEUM. 293 
According to Flickiger and arama gdh the districts of ai 
Chinese Empire which produce rhubarb extend over a vast ar 
‘«‘ They are comprised in the four northern proving of China Proper, 
cule as ceca Shansi, Shensi, and Honan; the immense no 
tern province of Kansuh, formerly ae included in Shensi, 
but now e eiadinn across the desert of Gobi and to the frontiers of 
Tibet; the province of Tsing-hai, inhabited by Mongols, which 
includes the great salt-lake of Koko-nor and the districts of Tangut, 
Sif: ay and sak aye and lastly, the mountains of the western 
ob i inquiries conducted on the spot in 18738, and sin in 
260; ‘that the true source of the finest Chinese ees is a plant 
very | similar to, if not identical with, R. palmatum,+ and found by 
him in the district of Tangut. The late M. C. J. de Maximowicz, 
in a letter to Prof. D. Oliver, dated 4th Aug. 1889, states that the 
rhubarb cultivated for the drug in Western Kansuh is certamly 
R. palmatum. The roots last sent by Col. Prjewalsky to St. Peters- 
burg ‘‘ were distributed to chemists and medical men there to be 
ted foun 
quantity of effective matter and action on the stomach.” Plants 
were also raised from seed, and yielded at first a drug of fair 
quality, but the roots soon deteriorated in the unfavorable climate 
of the Russian capital. Linneus at first thought that the source 
of officinal gnnber ae R. undulatum;{ after reading Prosper 
pinus’ eee it might be R. Rhaponticum,§ and 
subsoquanty. ‘efor ie to R. palmatum. 
It may be now to pba some of the generic charact 
in so far as they may indicate those on which the subdivisions “of 
the genus might be based. Meisner, in his grouping of the species, 
selected two characters as a basis of classification—the branching 
of the inflorescence, and the contour of the leaves. I am aid 
that neither of these can be depended upon as primary characters, 
though they may be useful in distinguishing onset in groups of a 
lower grade. 
Tur Leaves.—The ocree which sheath the thick stem, as well 
as those which sheath the base of the petioles, are dry an and scarious. 
The petiole is very variable in character, and may be terete, semi- 
cylindrical, bilaterally compressed, or poly mae and may be smooth 
* Pharmacographia, p. 446. 
+ The citation usually given for this plant i ins Linn. Fase. 4, e which i is not 
only misleading, but meaningless. E properly, 
“ Linn. fil. Pl. rar. hort. Upsal. fa 7.’ Linneus’ son was sagen cs 
first to aia the plant fully, ai it is briefly referred to on p. 531 of the 
seco! iti e Sp. frase m (1 hy wi 
a a R. Rhaharbarn 
¢ In Sp. paras ed. 1 } 
in the second edition, however, oe aise was mcr to R. undulatum, and this 
latter name is subscrib ed in Linnzus’ writing in his own copy of Amenitat. 
Acad. vol. iii. (1759), on the third page of Samuel Ziervogel’s thesis, ‘“‘ De 
§ De Rhapontico, Leyden, 1718 (written probably about 1610). 
