HORTICULTURE. 763 



self-fertile grains seem to be surrounded by a nuicilaginous substance wliieh makes 

 tliem stick to one another more or less, so tliat the i)ollen, whether it lies dry on the 

 slide or is placed in liquid media, arranges itself in a succession of clumps. This 

 nuicilagiuous sul>stance does not appear to l)e soluble in water, as the pollen grains 

 retain their position even after several days in the solutions. The self-sterile pollen, 

 on the other hand, shows no such arrangement, but the grains distribute themselves 

 either on the slide or in the liquid like so much dry powder, quite by chance." 



Microscopical examination of the pollen showed that with self-fertile varieties the 

 dry pollen grains were oblong, blunt at the ends, and quite symmetrical. The pollen 

 of the self-sterile sorts was more irregular, showing little of the symmetry of the 

 other class. Varieties that were partly self-fertile had pollen grains of the two classes 

 and intermediate forms. With these sorts the growths of pollen o])tained in dilute 

 sugar solutions were weak and had an unhealthy appearance. Experiments with 

 large numbers of these varieties indicated that the "percentage of pollen which 

 germinated did not vary widely from the percentage of self-fertile forms which the 

 microscope showed that particular variety to contain." Pollen of the different 

 varieties examined varied considerably in size, but there was no apparent connection 

 found between the size of the pollen grains and their germinating power. 



This lack of viability or potency of the pollen grains of self-sterile varieties is 

 believed to be the main cause of self-sterility of grapes and sufficient in itself to 

 account for this class of phenomena. The results obtained have an important eco- 

 nomic value in choosing pollenizers for self-sterile grapes, since they give a method 

 of selecting the best varieties for this purpose without waiting to make vineyard 

 trials l)y sacking, etc., heretofore necessary. The sexual status of varieties can also 

 ])e determined by this means within a single blossoming season. 



The management of greenhouses, E. Lonsdale {Pennsylvanui Dept. Agr. Bui. 

 97, pp. 41)- — Practical advice is given regarding such matters as ventilation, watering, 

 drainage, heating greenhouses, preparation of soil, control of insect pests and fungus 

 diseases, propagation of plants, and annuals for winter blooming. In the introduc- 

 tion to the bulletin a rather extended account is given of the culture of American 

 Beauty and some other roses. 



Mature v. immature lily bulbs, A. F. Woods {Florists' Exchcmgc, 14 {1903), 

 No. 16, p. 463, Jig. 1). — Fifty healthy plants of Liliiun harrisli, growing in one of the 

 best bulb fields of Bermuda, were selected to test the relative value of mature and 

 immature bulbs. Twenty-five of these plants were dug about the middle of May and 

 the bulbs shipped to the United States where they were stored in a cool place. The 

 remaining 25 plants were dug and shipped the latter part of July. At this time the 

 tops of tlie plants were dead. Both lots of bulbs were planted in pots in August in 

 the usual manner. The following winter the immature bulljs produced 64 per cent 

 of badly diseased and worthless plants and 36 per cent of poor plants, averaging but 

 4^ flowers each. The mature bulbs produced 68 per cent of good strong plants, 

 averaging 7 flowers each, and 32 per cent showing some disease of the leaves, but 

 even with these most of the flowers were all right. The plants were } taller than 

 those from immature bulbs. These results are believed to show clearly the great 

 desirability of mature bulbs. 



Statistics of horticultural products {Tit^elfth Census United States, Census Rpts., 

 vol. 6 {Agriculture, pt. 3) , pp. 377-399, 695-795). — Some of the general results secured 

 in the U. S. Census of 1899-1900 on the production of certain vegetables, fruits^ 

 flowers, etc., are briefly noted below. 



Vegetable culture. — In 1899, 5,753,191 acres or 2 per cent of the total area of the 

 country devoted to crops was planted in vegetables. The vegetables grown had a 

 total value of $238,846,908, which is al:)out 8.3 per cent of the total value of all farm 

 crops. The average value of all farm products per acre was $10.04, while for all 



21781— No. S— 03 1 



