350 



CROSSLWG RASPBERRIES AND CUCURBITS. 



Fig. 3. 



for raspberry stigmas to ripen in readiness to receive 

 pollen, if the bud was just about ready to open when the 

 stamens were removed. At this stage it will have some- 

 thing the appearance shown in Fig. 3. It will have 

 grown somewhat, the styles will be longer and more 

 spreading, while the stigmas have a rather shining sticky 

 appearance. My expetience seemed to in- 

 dicate that the blackberry requires more 

 time than this to properly ripen its stigmas, 

 three or four days not being too much. 

 Most of the work among the blackberries 

 was with the later blossoms; these gener- 

 ally appear to be feebler than the earlier 

 ones, and it may be that this, together with 

 lateness of the season, had something to do 

 with the slowness of the stigmas in ripen, 

 ing. Some of these, treated with raspberry pollen, pro- 

 duced achenes which reached nearly full size, but never 

 ripened, remaining in that condition till frosts came. 



Getting the pollen in just the right condition to work 

 nicely appears to be the most difficult part ©f all, for the 

 work is slow and uncertain if it is so green that it must 

 be broken out and laid on the stigmas to ripen. Remov- 

 ing buds just ready to open at the time of emasculating 

 those of the female parent, and keeping them in a safe 

 place while the stigmas are ripening, is an advantage. 

 Perhaps carefully covering them on the plant would be 

 still better. When the pollen dusts out freely, it is a 

 very easy matter to bring the stamens in contact with 

 the stigmas, leaving an abundance of pollen adhering. 



After this is done, the cluster must again be carefully 

 covered for a week or more, for if the pistils have not 

 been properly fertilized, they remain in a receptive con- 

 dition some time, waiting for the opportunity to perform 

 their natural function. After this danger is fully past, 

 the paper bags may be replaced by others made of mos- 

 quito netting, to protect the fruit from 

 birds and from being picked. These 

 bags admit light, and also aid in find- 

 ing the clusters, being more readily 

 seen than the label. 



Fig. 4 gives a general idea of the 

 appearance of a mature fruit which 

 has been crossed. The absence of the 

 calyx, which ordinarily covers the base 

 of the berry, is readily noticed, and 

 usually there will be parts in which the achenes remain 

 undeveloped, although in some cases perfect specimens 

 will be obtained. As a rule, we cannot expect to equal 

 nature's methods in pollinating. An apparent exception 

 to this occurred in the case of the dewberry, which here 

 produced only irregular, knotty fruits ; but in some in- 

 stances, when crossed by the blackberry, perfect speci- 

 mens were obtained. 



Over eighty clusters, averaging probably live or six 

 flowers in each, were crossed in the Cornell gardens in 

 the summer of 1890, and some excellent results obtained 

 so far as seeds were concerned. What the outcome wiU 

 be in the way of plants and the fruit which they will 



Fig. 



Fig. 



bear, of course, remains to be seen. It is quite probable 

 that in some cases of violent hybrids the seeds may not 

 have enough vitality to germinate, even when perfectly 

 formed, or the seed coat alone may have been developed. 

 Seeds were obtained from crosses between the black- 

 berry and dewberry, red and black raspberry, American 

 and European raspberries, raspberry and blackberry, 

 etc. 



A single attempt to cross the Shaffer with Riibus odor- 

 atiis, the wild purple-flowering raspberry, failed. This, 

 however, brought to notice the fact that a large portion 

 of the buds of this species were completely destroyed by 

 the presence in great numbers of small, white maggots, 

 larvae of a fly. So far as I could learn, little or nothing 

 's known of this enemy. Should its attacks ever spread 

 to cultivated species, it might prove very serious 



As a check upon the reliability of the results obtained, 

 three clusters were left covered 

 after emasculating, and no pollen 

 given ; these developed absolutely 

 nothing. This same method of 

 procedure applies to the straw- 

 berry, and as most of our larger 

 fruits also belong to the rose fam- 

 ily, the flowers have the same 

 general structure. 



Among the simplest plants up- 

 on which to do crossing are the 

 cucurbits, or melons, squashes, 

 etc. In this order the plants are 



generally monoecious, i. e., the stamens and pistils are in 

 separate flowers. These can always be readily distin- 

 guished before opening, for the female flowers bear the 

 young fruit, plainly visible at the base of the bud. 



In crossing these it is only necessary to apply the pol- 

 len to the stigma of the female flower, taking the neces- 

 sary precautions against mixing or allowing other pollen 

 to reach the stigma. By a little observation, one can 

 tell in the afternoon what flowers will open the next 

 morning, and the pollen from flowers of the same age 

 may be applied then ; or, both may be tied up to pre- 

 vent their opening by a single loop of raffia around the 

 tip of the corolla, and the pollinating done the following 

 morning. To do this, simply cut away the corolla near 

 the base with scissors or knife, plow the pollen out of 

 the anthers with a small pin scalpel, and apply to the 

 stigma. If ripe enough to dust out freely, the stamen 

 column itself may be touched to the stigma, leaving the 

 pollen. A word of caution may be needed against leav- 

 ing the flowers tied in this way long in the morning, for 

 insects readily eat through the corolla and perform the 

 pollinating to suit themselves. 



While the rule of entirely separate male and female 

 flowers is a general one in this order, there is an occas- 

 ional unruly variety, among the musk-melons at least, 

 which does not obey the botanist's rules, and bears sta- 

 mens in the pistillate flowers. These are so nearly con- 

 cealed that, unless on the watch for them, they are likely 

 to be overlooked and the value of the cross entirely lost. 



