[Vol. 8 
120 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
been have since disappeared. Besides other advances men- 
tioned elsewhere this group shows a change from sparingly lyrate 
leaves in L. densiflora to entire, oblanceolate leaves in L. Engel- 
mannii and finally to entire, ovate leaves in L. ovalifolia. Be- 
cause the pods in this group are not always quite sessile it may 
possibly have been derived from the gracilis group. 
3. L. montevidensis, although insufficiently known, has an 
aspect similar to L. Engelmannii and may be related to the 
preceding group. 
4. L. arctica, with its variety Purshii, shows no very close 
relationship to any other species and is thought to have arisen 
from some primitive species now unknown. Because of an 
apparent decrease in the number of ovules and the more fre- 
quent appearance of scattered stellae on the pods, the variety 
is thought to have been derived from the species. 
5. The argyraea group, previously mentioned as having the 
rays of the stellae unbranched, contains six species, L. argyraea, 
L. Berlandieri, L. purpurea, L. Fendleri, L. Schaffneri and L. 
pueblensis. In this group the second alone possesses pubescent 
pods but in other ways it is not so specialized as some of the 
related species. It has probably been directly derived from L. 
argyraea. The other species may have had a common ancestor 
more primitive even than L. argyraea. This was certainly the 
case with L. Fendleri. L. purpurea and L. pueblensis, although 
distinguished from the others of this group by their recurved 
pedicels, are-not on this account thought to be closely related. 
Each of the species in the group stands apart from the others 
as a distinct unit. 
6. The recurvata group also includes six species, L. recurvata, 
L. pallida, L. aurea, L. argentea, L. arenosa, and L. macrocarpa. 
All these species possess recurved pedicels, stellae with forked 
rays, and globose pods that are either glabrous or pubescent. 
L. pallida and L. aurea seem to represent terminal groups derived 
from L. recurvata. Like it they are annuals. L. aurea is of 
partieular interest because the reduction in the number of ovules 
is extreme and the capsules are either glabrous or stellate-pubes- 
cent. L. argentea, L. arenosa, and L. macrocarpa are perennials 
with densely pubescent pods. ZL. argentea, it is believed, has 
been derived from L. recurvata, although in some respects L. 
