38 
PLANTS OF YELLOWSTONE NATIONAL PARK 
Siberian onion ( Allium sibiricum) is the only wild onion in the park 
that has cylindrical, hollow leaves like a cultivated onion. The 
others all have flat leaves. The flowers of this species are lavender- 
colored and rather crowded in the umbel. 
AUium rubrum is most easily recognized by the fact that most of 
the flowers of the umbel are replaced by small, spherical bulblets, 
red in color. The few flowers are white, the three outer parts of 
the perianth often with a dark green midnerve. 
Allium nuttallii is very similar to the preceding species, except 
that it produces few if any bulb- 
lets. The flowers vary from rose 
to white. 
Nodding onion ( Allium cer- 
nuum) is easily recognized by the 
fact that the upper end of the flow¬ 
ering shoot is curved over, so that 
the umbel is nodding and the 
flowers hang downward. The 
flowers are rose color or white, 
and the stamens are. longer than 
the parts of the perianth. 
Allium brevistylum is most 
readily distinguished from A. 
nuttallii by the bulb which is 
stout and has an elongated base 
like an underground stem, and 
is covered by a thin mem¬ 
brane like a cultivated onion 
instead of a fibrous covering. 
The umbel is erect and few-flowered, the flowers being deep rose 
color. The parts of the perianth are about twice as long as the sta¬ 
mens and pistil and are rather narrow. 
Allium brandegei.— 2 The flowers of this species are very similar 
to those of the preceding one, except that the parts of the perianth 
are broadly lance-shaped. There are only two leaves, but these are 
longer than the flowering shoot. The bulb is very small and has a 
membranous coat. 
In addition to the above Allium tolmiei has been reported as 
occurring in the park. 
Camas ( Camassia esculenta) grows from a bulb which was formerly 
much used by the Indians as food. The leaves are basal and some¬ 
what grasslike. The flowering stalk is quite stout, 1 to 2 feet high, 
and bears a raceme of blue flowers. 
