VEGETATION OF FLATHEAD LAKE 359 



The beach trees are : 



Populus trichocarpa (Hook) T. & G. 



Crataegus douglasii Lindl. 



Alnus tenuifolia (L) Nutt. 



Cornus stolonifera Michx. 



Betula occidentalis Hook. 



Betula alba L. 



Salix lasiandra Beuth. 



Salix fiuviatilis Nutt. 



Pinus ponderosa Dougl. 



Juniper us virginiana L. 



The juniper, commonly called red cedar, is the most character- 

 istic tree of the Flathead Lake shore, growing on all the islands. 

 Some of the old trees are making a hard struggle for life. Their 

 crooked branches have been beaten by the storms of many winters 

 and their roots have been exposed by the scraping of ice and logs. 

 There are large yellow pines growing on the beach in many 

 places. It seems reasonable to suppose that these trees are sur- 

 vivals of a time when the present shore was above high water 

 mark. It would be impossible for seedlings of either pine or 

 juniper to get a start under present beach conditions. This may 

 be due to climatic changes affecting the precipitation of the 

 region. The climax forest has advanced to its limit of extension 

 under the present conditions. The pioneer plants of the stony 

 beach succession are much the same as in the rock shore suc- 

 cession. The shrubs are also the same. Rhus toxicodendron L. 

 is common, spreading over the stony beaches and back into the 

 woods. Oenothera biennis L. and Asclepias speciosa Torr. have 

 made their appearance on the shores and now seem quite at home. 

 Helenium autumnale L. is one of the showiest of the beach plants. 

 The purple spikes of the false dragon head, Physostegia parviflora, 

 contrast well with the yellow wheels of Steironema ciliatum. 



The following plants were noted on the beach at Safety Bay on 

 August 7: 



Erigeron speciosus DC. 

 Pentstemon acuminatus Dougl. 

 Balsamorrhiza saggittata Nutt. 

 Lupinus ornatus Dougl. 

 Chrysopsis villosa (Pursh) Nutt. 



