OF NORTH AMERICA. 15 
508. Sorbus riparia Raf. Autikon. Branch- 
es rugose, folioles 9 to 15 oblong sessile, base 
oblique entire, end acute equaly mucronate 
serrate, odd leaf petiolate broader acuminate ; 
corymb paniculate, berries pisiform globular. 
— A small tree 10 to 20 feet high, growing on 
the margins of Rivers, the Missouri, upper 
Mississippi, lower Ohio, Wabash, Illinois; but 
rare. The fruit is very small commonly of a 
saffron color with 3 seeds oval compressed in- 
closed in a tough shell, and thus nearly a drupe 
sometimes only one seed by abortion. Near 
S. microcarpa , which however has folioles 
acum. unequally serrate, not obliquate, berries 
scarlet and larger. Here the folioles are 2 or 
3 inches long, pale beneath, quite smooth, pe- 
tiols compressed at the base. The genus Sor- 
bus must be preserved, although some writers 
wrongly unite it to Pyrus : it is known at 
first sight by the pinnate leaves, and the calix 
not persistent nor crowning the fruit. It would 
be better to unite to it all the tristyle sp. of 
Crategus than to abolish it. 
509. TRILOPUS Mitchell, or HAMAME- 
LIS Linneus, name posterior ? This G* has 
puzzled the Botanists, Jussieu wrongly united 
it to Berberides. It has now be made the sin- 
gle type of the Ham am elides ; but it is so near 
to my Scleranthides, that it must probably be 
united thereto as a subfamily. Only 3 species 
were known; besides the doubtful varieties of 
Walter; but I have observed 6 species, and 
therefore shall now give their Monograph. They 
may be called hyemal shrubs, since they blos- 
som late in the autumn, after the leaves have 
begun to fall. 
510. Tr. or H. vxrginica Raf. med, fl. tab. 
