2 ERYTHEA. 



ready, when the banner erects itself, to be forced out of the small 

 opening at the end of the keel by the piston-like filaments of the 

 other stamens. The style is a little longer than the filaments and is 

 easily extruded by pressure on the keel, I have not determined at 

 what period the minute stigma becomes receptive, nor whether it is 

 fertile to its own pollen. In spite of the underlying circle of bristles 

 some of its own pollen must fall on the stigma after an insect visit, 

 but the stigma is sure to be first brought into contact with any pollen 

 the guest may bring from other flowers. The flowers provide no 

 honey. This species, for obvious reasons, is visited more than 

 lupines usually are by bees collecting pollen. A large bumblebee, 

 Bombus Nevadense, Cress., is often seen on the plants, and this bee 

 works very rapidly. I have seen it visit thirty-five flowers in one 

 minute. It has but to clutch a keel with a leg, and the pollen is 

 pumped up on the under side of its body, soon to be deftly stowed 

 away in the baskets. Hive -bees work less rapidly, pausing with 

 their entire weight on each keel^as if about to collect honey. 



LupiNUS Breweri, Gray. The flower-clusters of these typically 

 alpine plants are only about two inches long and the flowers four or 

 five lines long, but both the individual flowers and the flower clus- 

 ters are of unusually long duration. The flowers are slightly fra- 

 grant. They were under my daily observation for two months, but 

 only three times did I see them visited by insects, twice by a hive 

 bee and once by Bombus Calif ornicus. 



PoTENTiLLA Wheeleri, Wats. These plants are scattered over 

 acres in the vicinity of the lake. The stigmas are mature when 

 the flowers first open early in the day. Dehiscence does not begin 

 until about noon of the first day, and at first the pollen can not fall 

 on the stigmas ; later the stamens rise somewhat, and there may be 

 some self-pollination, as there must be when the flowers close toward 

 evening. When the flowers open the second day, they are practically 

 stamiuate, the stigmas having withered, and the center of the flower 

 is occupied by the dusty upturned anthers, whose pollen is available 

 for the cross-pollination of flowers in the pistillate stage. Honey is 

 fairly abundant, and the flowers are visited from early morning by a 

 considerable number of guests. As is usual in this type of open flowers 



