September 21, 1892.] 



Garden and Forest. 



451 



tive use in Messrs. Williams' group. The great floral 

 feature of the show, however, was the Begonia trophy of 

 Messrs. Laing, who quite surpassed themselves. Never 

 before at any show has such a marvelous array of double 

 and single Begonias been seen. They were arranged in 

 a rising bank with a background of Palms and other foli- 

 age, and disposed in groups of one color a yard or so 

 square ; the effect was brilliant in the extreme. The colors 

 ranged from pure white through pale and deep yellows 

 and warm orange up to the most intense scarlets and crim- 

 sons. The gold medal won by the exhibitors was highly 

 merited. jv n a ■ 



Cultural Department. 



The Self-pollination of the Grape. 



THE Grape' has small greenish blossoms which open 

 in a peculiar and interesting way, and protect the 

 stigmas from outside pollen till they have opportunity to 

 become self-fertilized. The petals form a kind of cap which 

 covers the sexual organs. When the flower opens the 

 petals break away from their attachment at the base, but 

 remain fastened to each other at the top, thus keeping the 

 stigma and anthers covered. Finally the petals curve out- 

 ward from the base and upward, and the expansion of the 

 stamens usually dislodges the cap. In the nearly related 

 genera, Cissus and Ampelopsis, the petals open at the top 

 and expand in the usual way. The calyx in all Vitacefe is 

 practically obsolete, and plays no part in the opening of 

 the flower. 



An opening bud is shown in Figure 75 ; a being a petal 

 just detached at the base, and curved outward, disclosing a 

 portion of a tilament {h), and the outline of a part of the 

 pistil. Figure 76 shows the pistil with the cap removed, 

 and illustrates the expansion of the different forms of sta- 

 mens. If the flower has short filaments, as at a, they be- 

 come reclined (6), or recurved (c). If the flower has long 

 filaments {d) they become erect, as at e. This structure of 

 the Grape-flower is of practical interest to the grower, and 

 we are glad to give a study of the subject in a paper read 

 before the American Association for the Advancement of 

 Science at its meeting in Rochester last month by Professor 

 S. A. Beach, of the New York State Experiment Station. 



The best time for examining Grape-buds, to find out whether 

 self-pollination takes place before the flower opens, is just at 

 the time when dehisence of the corolla begins. Dehisence 

 usually begins at the base of one of the petals, and extends up- 

 ward half or two-thirds of its length. Afterward the straight- 

 enmg up of the stamens, if they have long filaments, or the 

 reclining or recurving of the stamens, if they have short fila- 

 ments, dislodges the calyx, or cap, as it is frequently called, 

 and carries it upward and to one side, thus uncovering the 



hisence of the corolla allows the moisture to escape from the 

 open antiiers, and the pollen, becoming dry, is discharged abun- 

 dantly on the pistil before the cap is 'displaced, thus insuring 

 self-pollination before the stigma is exposed to foreign pollen. 



^'g- 75-— The Opening Bud of a Grape- Fig. 76.— Pistil and Stamens of a Grape- 

 fiower. flower. 



Stigma. Occasionally the filaments fail to perform this work, 

 and the cap persists for an indefinite period, as a withered 

 covering on the apex of the young fruit. 



The anthers are already opened when dehisence begins, but 

 the pollen has not yet been discharged from them. The de- 



F',?- 77.— Two clusters of tlie Lindley Grape from the same vine, with ib jrlive 

 fruits showing lack of proper pollination. 



In every instance when buds could be found in the right 

 stage of development it was observed that self-pollination 

 occurred before the blossoms opened. The total number of 

 individuals in which self-pollination was thus observed is 

 seventy-seven, distributed among eight species and their hy- 

 brids and crosses. Several other varieties were examined 

 without being able to demonstrate that self-fertilization occurs 

 before the blossoms open, but in no case was this true when 

 buds could be found at the proper stage of development 

 above noted, namely, just beginning dehisence. 



Clusters o£ grapes were inclosed in paper bags before the 

 blossoms opened and were allowed to remain covered until 

 the blossoming period had passed. This effectually shut out 

 foreign pollen and made it possible for the stigmas to be pol- 

 lenized only by pollen from stamens of the same Hower or of 

 the same cluster. Some results of these tests may be briefly 

 summarized as follows : 



Of four cultural varieties having pure Labrusca blood, three 

 were found to be fully self-fertile, and the fourth nearly so. 

 Their stamens in every case are borne on long filaments and 

 self-pollination occurs before the blossoms open. 



Of seventeen hybrids of Vitis labrusca and V. vinifera, 

 three were fully self-fertile. These have long filaments. 

 Whether self-pollination occurred before the blossoms opened 

 was not noted. Another one, though not fully self-fertile, 

 still developed a large per cent, of the ovaries into perfect 

 fruit. It has long filaments. Self-pollination occurs before 

 its blossoms open. Eleven proved to have pollen self-irritant 

 only — that is, the ovaries started to develop and soon fell away 

 or persisted as abortive fruits. Ten of these have short fila- 

 ments. The character of filaments of the eleventh one was not 

 noted. Self-pollination was observed with seven of this class. 

 Whether it occurs with the other four cannot be stated. One 

 proved to have pollen impotent — that is, the ovaries were not 

 incited to any perceptible growth. It has short filaments and 

 self-pollination occurs before the blossoms open. 



One cross of V. labrusca having vinifera blood was found 



