All use subject to University of Chicago Press Terms and Conditions (http://www.journals.uchicago.edu/t-and-32 BOTANICAL GAZETTE [JULY as well as in showing the variation in time of the occurrence of certain phenomena due to varying climatic conditions of different seasons. It is interesting to note that the different stages of development as worked out by NOREN from material collected in Sweden were, in general, from three to four weeks later than corresponding stages in the material collected at Wellesley. MALE GAMETOPHYTE Both J. communis and J. virginiana are dioecious, occasionally monoecious. RENNER (2i) reported the presence of hermaphrodite flowers in J. coinmunis. I searched for similar flowers during the period of collection, but was unable to find any. The microsporangia were fully developed and the microspore mother cells were already present in J. virginiana on March 28, but in J. communis the microsporangia were not differentiated until April i3. The sporophylls are cyclic in arrangement and are disposed in whorls of three, with the microsporangia on the under side next to the axis of the cone (fig. i). On April 25 the cells of the archesporial tissue were undergoing their last division before the formation of the microspore mother cells. Following this division, each microsporangium consists of a central mass of polygonal microspore mother cells; surrounding these is a single layer of tapetal cells, rich in protoplasm and containing large nuclei, and a wall of two layers of cells (fig. 2), as has been described by other writers. The cells of the outer or superficial layer of the wall are large and tabular. They contain considerable resin, which causes them to stain diffusely. Very soon after the differentiation of the microspore mother cells the heterotypic division begins. LOPRIORE (i8) reported that the microspore mother cells of Araucaria Bidwillii also undergo a very short period of rest before this division is entered upon. As soon as the walls are formed about each microspore, the mother wall breaks down, setting the spores free in the sporangium. The microspores increased in size and were shed May iI. The mature pollen grains of Juniperus do not differ as to content from the microspores. In the spring of i903 pollination took place in J. virginiana on April 22, but in the spring of I905 not until May 9. There is, then, a variation, due to seasonal or climatic conditions, of

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This paper is based upon a study of slides made through a series of years for class use in the Botany Department of Wellesley College. The material was taken from greenhouse plants of the rose or bright pink variety of Impatiens Sultani Hook. The bright red and light pink varieties also were growing in the greenhouse, but care was taken to collect material from the rose-flowered plants only. Some of the plants from which the flowers were collected were chance seedlings. No attempt was made to determine whether or not these were a pure strain of the rose-colored form. In BAILEY'S (4) Standard Cyclopedia of Horticulture the original form of 1. Sultani is given as a rich scarlet, shades ranging from pink to almost purple being found on hybrids or sports. If this be true, then all the rose-colored forms used for this study are either hybrids or sports. According to BAILEY the species I. Sultani was originally found in Zanzibar and named by HOOKER in honor of the Sultan of Zanzibar. In ENGLER and PRANTL'S Die Natirlichen Pfianzenfamilien (i6) it is cited from Sierra Leone, Western Africa. It is stated in GRAY'S Manual that the Balsaminaceae often contain two kinds of flowers, the large showy ones which rarely ripen 289