290 



Lovers of cacti sometimes pull their plants from the pots in winter and let 

 them shrivel, so that they may bloom more freely. In this case nitrogen is 

 not lacking but the scarcity of water causes the plants to make use of the 

 elaborated food in flower production. 



In treating of the bearing of sterile blossoms, due to insufficient water, 

 Oberdieck^ reports that, as a result of drought, the blossoms of large- 

 flowered pansies drop prematurely while, with sufficient moisture, they 

 develop the seed capsules. Double zinnias behave in the same way, like- 

 wise the red flax and often, indeed. Phlox Drummondii. Garden beans do 

 not set so well in dry years. Raspberries and strawberries give small, poorly 

 seeded fruits. In the case of the ever-flowering wood strawberry there is 

 a degeneration with continued drought, making the plants resemble the 

 "Vierlandcr strawberries," since they no longer develop fertile blossoms. 

 Zacharias- states that the latter variety of strawberries is one which is 

 usually either staminate or pistillate, hut rarely monoecious. He is of the 

 opinion that pollination is incomplete where only a few staminate, so called 

 "wild" plants, distinguished by their weaker growth, weaker runners and 

 lower growing inflorescences with larger blossoms, are present on the fields. 

 He emphasizes the fact that invariably few pistils develop, so that only a 

 portion of the swollen receptacal is covered. We would lay the chief weight 

 on the latter point and advise remedially a change of soil and variety. 

 Zacharias recommends putting more staminate plants among the pistillate 

 ones. 



Phenomena similar to those in the Vierlander strawberry have been 

 observed in the black currant^. The sterility is said to be caused neither by 

 dryness nor by a shady position, but is ascribed by practical workers to a 

 varietal peculiarity. Likewise complaints are made as to the scanty setting 

 of fruit in the Schattenmorelle (shad,ow Amorelle cherry). The "Praktische 

 Ratgeber" (Practical Adviser) advises in grafting the taking of scions only 

 from the trees of that variety which experience has proved to bear well. 

 We often meet with such indications of the inheritance of undesirable 

 peculiarities. 



Numerous statements may be found in regard to the increasing pre- 

 dominance of staminate over pistillate blossoms. One of the earliest is 

 the statement by Knight, that melons and cucumbers at higher temperatures 

 without sufficient light almost always produce only stamens. Manz*, in his 

 experiments, comes to the conclusion that in monoecious as well as in 

 dioecious plants drought favors the development of male plants, while 

 moisture and good fertilization favor female plants. It is said that male 

 plants can be made to bear perfect blossoms by removing whole branches. 

 This might then indicate that the nitrogen taken up by the roots is now dis- 

 tributed among a lesser number of blossoms and thus better nourishes these. 



1 Oberdieck, Deutschlands beste Obstsorten, p. 9 footnote. Leipzif, 1881. 



2 Zacharias, E., t)ber den man^elhaften Ertras der Vierlander Erdbeeren. Verb, 

 d. Naturw. Vereins, Hamburg-, 1903. 3. Folg-e, XI, p. 26. 



3 Prakt. Ratgeber im Obst- und Gartenbau. Frankfurt a. O., 1904, No. 10. 



4 Vierte Beilage zur Flora, 1822, Vol. V (after Hoffmann loc. cit.), p. 88. 



