478 
SYNGENESIA NECESSARIA. 
4. Paniculata. Mich. 
A. caule ramosissi- 
mo, superne paniculato, 
petiolisque villosis; fo- 
lds utrinque viridibus 
bipinnatifidis, laciniis 
lanceolatis; fructibus 
aggregatis, pusilIis,glo- 
boso-obovatis, subin- 
ermibus. 
Stem branching, pa- 
niculate at the summit, 
and with the petioles 
villous; leaves green 
on each surface, bipin- 
natifid, the segments 
lanceolate; fruit some- 
what clustered, small, 
obovate, slightly arm- 
ed. 
Mich. 2. p. 183. Sp. pi. 4. p. 376. Pursh, 2.p. 581. Nutt. 2. p. 186. 
Iva Monophylla, Walt. p. 232. 
Root annual. Stem two to four feet high, branching, pubescent and 
hairy, somewhat scabrous. Leaves alternate, the lower compoundly, the 
upper simply pinnatifid, the segments all acute, somewhat hairy and sca- 
brous. Flowers in simple racemes, terminal and axillary, the lower fertile, 
the upper sterile. Calyx of the sterile florets turbinate, ten-flowered, irre- 
gularly ten-toothed. Corolla globose. Stamens five, united on a pedicel. 
Fruit slightly muricate near the summit. 
Grows in cultivated ground — very common. 
Flowers July-— September. 
XANTHIUM. Gen. Pl. 1426b. 
Monoicum. Floris 
masculi — receptaculum 
paleaceum; antherce 
approximate non coa- 
lite; involucrum poly- 
phyllum, imbricatum, 
mulliflorum. Floris 
foem. involucrum 2- 
phyllum, 2-florum; co- 
rolla 0; drupa sicca, 
muricata, 2-fida. Nux 
2-locularis. 
Monoecious. Male 
Jlorets — receptacle chaf- 
fy; anthers approxi- 
mate, not united; invo- 
lucrum many leaved, 
imbricate, many flow- 
ered. Female Jlorets — 
involucrum 2-leaved, 
2- flowered; corolla 0; 
drupe dry, muricate, 2- 
cleft; nut 2-celled. 
