A STUDY IN PLANT VARIATION 269 



31. Wangenheim, F. A. BeschrcibunReiniscrNordamerikanischerHolz-und Busch- 



arten mil Anwendung auf deutsche Forsten, 1781, 103. 



32. " " Beitrag zur teutschen holzgerechten Forstwissenschaft, 



die Anpflanzung Nordamerikanischer Holzarten, mit 

 Anwendung auf teutsche Forste, betreffend, 1787. 



33. Wight, W. F. Native .\mcrican Species of Prunus. Bull. 179. Bur. 



Plajit Ind. U. S. Dept. of Agri., 1915, 55. 



34. Willdenow, K. L. Enumeratio Plantarum, Vol. 1, 1809, 519. 



VII. EXPLAN.\TION OF PlATES 



Plate LXVT 

 Fig. 1 Branching form of P. maritima var. coeridea magna, in winter condition. 



Fig. 2 Branching form P. maritima var. purpurea magna, in winter condition. 



Fig. 3 Branching form P. maritima var. rubra parva, in winter condition. 



Fig. 4 Branching form P. maritima var. lutea magna, in winter condition. 



Plate LXVTI 

 Fig. 5 Blossoming branch P. maritima var. coerulca magna. 



Fig. 6 Blossoming branch P. maritima var. purpurea magna. 



Fig. 7 Blossoming branch P. maritima var. rubra parva. 



Fig. 8 Blossoming branch P. maritima var. lutea parva. 



Plate LXVIII 

 Fig. 9 Cross section of stem P. maritima var. purpurea parva, showing rings of 



cork and phloem. X 25. 

 Fig. 10 Cross section of stem P. maritima var. coerulea magna, showing elements 



of structure. X 25. 

 Fig. 11 Stipule of P. maritima var. coerulea magna, showing glandular serrate 



structure. X 10. 

 Fig. 12 Cross section of midrib P. maritima var. rubra magna. X 25. 



Fig. 13 Lower epidermis of P. maritima var. coerulea magna, showing stomatic 



islands and conglomerate crystals of calcium oxalate. X 160. 



Plate LXIX 

 Fig. 14 Fruits (natural size) P. maritima var. coeridea magna and var. coertdea 



parva. 

 Fig. 15 Fruits (natural size) P. maritima var. purpurea magna and var. purpurea 



parva. 

 Fig. 16 Fruits (natural size) P. maritima var. praecox showing bloom. 



Fig. 17 Fruits (natural size) P. maritima var. lidea magna and var. lutea parva. 



Plate LXX 



Fig. 18 (a) Seeds (edge and end views) P. maritima var. coerulea magna. 



Fig. 18 (b) Seeds (edge and end views) P. maritima var. coerulea parva. 



Fig. 19 Seeds (edge and end views) P. maritima var. praecox. 



Fig. 20 (a) Seeds (edge and end views) P. maritima var. purpurea magna. 



Fig. 20 (b) Seeds (edge and end views) P. maritima var. purpurea parva. 



Fig. 21 (a) Seeds (edge and end views) P. maritima var. rubra magna. 



Fig. 21 (b) Seeds (edge and end views) P. maritima var. rubra parva. 



Fig. 22 (a) Seeds (edge and end views) P. maritima var. lutea magna. 



Fig. 22 (b) Seeds (edge and end views) P. maritima var. lutea parva. 



