OBSERVATIONS OX THE BEACH PLUM 

 A STUDY IN PLANT VARIATION 



BY 



John Young Penn>-packer, A.M., Ph.D. 

 With Plates LXVI-LXX 



(Thesis presented to the Faculty of the Graduate School 



of the University of Pennsylvania, May 1915, 



in partial fulfilment of the requirement for 



the Degree of Doctor of Philosophy). 



CONTENTS 



I. iNTRODrCTlON AND HiSTORY 232 



1. Introduction 232 



2. Previous literature 232 



?,. Material and methods : 235 



4. Distribution 235 



(1) Along the coast 235 



(2) Inland 237 



5. Habitat and Environment -'-'o 



II. Structure of Prunus Maritima 239 



1. Stem 239 



2. Leak 240 



3. Flower 243 



4. Fruit "" • 244 



III. Classification of Varieties 250 



1. Prunus maritima var. caeruleo magna 251 



2. Prunus maritima var. caeruleo parva 253 



3. Prunus maritima var. praecox - • 254 



^. Prunus maritima var. purpurea magna 255 



5. Prunus maritima var. purpurea parva 257 



6. Prunus maritima var. rubra magna ■ 258 



7. Prunus maritima var. rubra parva 260 



8. Prunus maritima var. lutea magna 261 



9. Prunus maritima var. lutea parva 263 



rV. Economic Value 264 



V. Summary •"• • 266 



VI. Bibliography 268 



VII. Explanation of Plates ■ 269 



