294 PRIMARY CHARACTERS IN THE SPECIES OF RHEUM. 
or furrowed on either surface, or both. The lamina of the leaf is 
large and spreading, and either entire, undulato-crenate or sinuato- 
dentate, rarely divided into laciniated lobes (only in R. nein 
The number of nerves are usually 3-7, but vary from mi in 
iene st prec of R. rhizostachyum to a single prom eninatit te 
in R. uninerve and R. pumilum, two species deseribed by Maxiinowied 
T weERS.—Meisner divides the genus into three sections. 
The siaralter which he gives as diagnostic of the third section 
which includes three species) are—‘‘Racemi spiciformes, indivisi. 
Folia indivisa. Pedicelli fasciculati, infra medium articulati.’” A 
few remarks on these characters will partly illustrate the object of 
this paper. As to the first character, the only apparent difference 
between ‘‘racemi paniculati” and ‘“racemi spiciformes, indivisi’’ is 
anching is 
such as can be seen in R. undulatum. From the forks of the lowest 
and second leaves. there are rarely any flowers. Taking an upper 
leaf, from the base of the petiole spring three peduncles, of which 
the central is much longer and more vigorous than either of the 
the rhachis. As to the second sae acter, it is noted in the previous 
paragraph that all the species have ‘‘folia indivisa,” except R. 
palmatum. Throughout the oer it is certainly unusual for the 
pedicels to be otherwise than ‘infra medium articulati.” In 
garden pbei mens I have fre ricoh slétiosd variation in the articu- 
i e n herbariu im 
species included in the secti ight conveniently be fused: R. 
spiciforme and R. Moorcroftianum are scarcely to be distineralahad: 
even ‘‘on paper.” 
Catyx.—The floral envelope is simple, with traces of a differenti- 
ation into two whorls. By ae it is called a corolla, by 
, an 
last term is to be preferred. « -Petianthium,” a Linnean term, has 
been objected to, because it etymologically denotes something 
round the flower, but it seems not hes eon for the envelopes 
a surround the essential of the Pe 
ter the 
