[Vol. 8 
106 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
Because these structures are relatively stable the few differences 
they do present are often of great value in determining larger 
circles of relationship and as such are of unusual interest. The 
sepals are of two nearly equal pairs. They are never truly sac- 
cate at the base and are always pubescent with trichomes similar 
to those borne on other parts of the plant. The petals vary 
from obovate to narrowly spatulate. They are always entire 
and there is no distinct differentiation between blade and claw. 
The broader form is prevalent among the annual species with 
pinnatifid leaves and presumably represents the original type 
more closely than the narrow form that is common among the 
perennial, rosette-forming members of the genus. 
The petals are usually yellow and this is undoubtedly to be 
regarded as the primitive color. In a few species it is pale and 
variously tinged with red or purple, as in L. pallida, L. pur- 
purea, and L. pueblensis. A more common departure from the 
normal is found in a number of the more recent forms of widely 
different groups in which the yellow gives place to a red pigment. 
This red color may be present only on the tips of the petals as 
a narrow border or may extend nearly to the base. In some 
species it apparently appears as the flowers wither. Always its 
presence or absence is to be regarded as-of little significance in 
the determination of specific limits. This variation has been 
noted in L. argyraea, L. Fendleri, L. Berlandieri, L. arenosa, L. 
cinerea, L. Kingii and L. utahensis and probably occurs in many 
others. It is of interest to note here that a similar color change 
occurs in some species of the related genus Physaria. 
The stamineal filaments present a single character of consider- 
able significance: a conspicuous broadening or dilation at the 
base, which in its extreme is quite abrupt. Of the six species 
that show this dilation in a considerable degree, one, L. Lescurii, 
occurs in the section Alysmus, one, L. lasiocarpa, in Enantio- 
carpa, and four, L. auriculaia, L. grandiflora, L. densiflora and 
L. angustifolia in Eulesquerella. The four species possessing 
auriculate cauline leaves, previously considered as most primi- 
tive, also possess filaments with dilated bases. The remaining 
two are primitivein many respects and have certainly not been 
derived from any more primitive species now existent. All six 
are annuals and in all six the terminal bud is uninhibited. There 
