A STUDY IN PLANT VARIATION 243 



tains crystals. The crescentic shaped patch of xylem consists of a 

 mass of woody or lignified tissue. Its elements are arranged as a radiat- 

 ing series of cells. These are surrounded on the lower side by a cres- 

 centic patch of phloem in the outer zone of which are numerous mucilage 

 cells and crystals of calcium oxalate. 



3. Flower 



The flowers of P. maritima are white, with a pinkish tinge in the 

 blue and in the purple varieties. This is especially noticeable in the 

 sepals and stamens after the petals have fallen, although some of the 

 purple variety have decidedly pinkish petals. They are borne in umbels 

 with 2 to 5 flowers (usually 3) in a cluster near the ends of the youngest 

 twigs, or on the short lateral spinescent branches of the older wood. The 

 period of blooming lasts from ten days to two weeks. It ranges from 

 April 19th, for the small inland blue (observation made at Hainesport, 

 N. J.) to May 15th for the late varieties at Cape May Point. In most 

 of the varieties the blossoms appear before the leaves, yet in some of the 

 more protected bushes the leaves are well developed before the blossoms 

 fall. Evidence of this may be seen on some of the accompanying plates. 

 The writer has no accurate date as to the periods in other places north 

 and south, but their relative periods of blooming can easily be approxi- 

 mated from the time stated for the New Jersey varieties. The pedicels 

 are very pubescent; the hairs on the reds and purples being the longest, 

 while those on the blues and yellows are relatively short. The sepals 

 are green with pinkish margins as noted above, concave, pubescent, 

 uniting to form a campanulate receptacular tube 2 to 3 mm. deep. The 

 deepest cups are found on the varieties bearing the larger sized fruits. 

 The sepals vary in length from 2 to 4 mm. and from 1 to 2 mm. in width. 

 The outer surface of the receptacular tube is very pubescent, while the 

 inner concave surface is completely overspread by an orange yellow 

 glandular tissue which secretes the abundant nectar. The petals are 

 white with a slightly pinkish tinge in the blue and purple varieties, 

 rounded at the apex and contracted at the base into claws. They vary 

 in width from 4 to 7 mm. and in length from 6 to 10 mm. The corolla 

 spreads out to form a relatively flat surface of which the diameter is 

 15 to 20 mm. in the large and 10 to 15 mm. in the small varieties. The 

 stamens are variable in number, but usually about 30 of which some are 

 frequently abortive; 25 being the average number in the small inland 

 blue, 35 in the large blue black. These vary in length from 1-2 mm. 

 in the small abortive ones nearest the center, to 5-10 mm. in the outer- 

 most ones, and are inserted on the edge of the receptacular tube. The 



