Billeder på siden
PDF
ePub

they are here reproduced, natural size. A normal, uninjured flower is shown in Fig. 55. Inside the five white petals or leaves are seen the numerous sprawling stamens or so-called male organs, each one bearing an enlargement or anther on the end, inside which the pollen is borne. In the center of the flower is the head or cluster of pistils or so-called female organs, each of which ripens little grains which go to make up the blackberry.

Fig. 56. Flower ruined by frost.

into one of the

[blocks in formation]

Fig. 57. Blackberry fruits ruined by frost.

center of the flower
bore only a small
black column of dead
pistils (see Fig. 56).
Now and then, one
or more of these
pistils in the head

escaped, and developed into a
fruit-grain, SO that the berry
became a nubbin. Fig. 57 shows
the dead and aborted fruits at
picking time. At the top of the
pture are some fruits
fruits (N, N,)
in which one or two grains or
drupes are full grown, whilst the
rest of the berry failed to develop."

Frost Injury to Flowers.

325

Upon the 8th of May, 1897, a temperature of 27° (5 degrees of frost) was recorded by self-registering thermometers hung in fruit trees at Cornell, but no injury resulted. At this time, all the petals had dropped from apricot flowers, but the calyx ring had not yet fallen from the young fruits; peach flowers were in full bloom, but their fertilization had mostly taken place; Japan plum flowers were just dropping, and pear flowers were open, but not yet fully fertilized.

[graphic]
[graphic]
[blocks in formation]

is even insisted by Fig. 58. Frost injury on young Kieffer pears. some careful observ

ers that they sometimes recover even if frozen solid shortly after they are "set," the fruits failing to develop perfect seeds thereafter.* Fruits which are

*"The freeze of May, 1895, froze the fruit solid. The center of each pear turned black, and yet they persisted in growing. There were eighty barrels. I doubt if there was a seed or core in the whole lot. The quality was the best that I have ever seen."-Extract from letter from Benj. F. Hawes, Oakfield, N. Y.

simply frost-bitten,- that is, injured by a deposit of white frost,- are very likely to persist, but to show blemishes or deformities even at maturity. A common effect of very late frosts is to leave a distinct russet zone upon the fruit. . This zone marks the position of the frost upon the young fruit. Apples and pears are usually still erect when these frosts occur, and the dew,-which, when frozen, is frost,probably settles in a ring or belt near the top of the fruit or midway down it. The exact position and conformation of this deposit of dew are, of course, determined by the shape, position and exposure of the fruit. Figs. 58 and 59 show the frost

zones on

[graphic][graphic][graphic][graphic][merged small]

young pears and apples. This injured, corky tissue has the power of increasing itself by the extension of the abnormal cells, so that the zone is likely to

Injuries to the Fruits.

327

widen with the growth of the fruit.

Mature fruits,

with the rusty frost marks still conspicuous, are seen

[merged small][merged small][graphic][graphic][merged small][merged small]

tissue in the injured zone seems to be slow, resulting in a constriction of the fruit at that point.

Amongst the most serious results of very late frosts in the north are the injuries to vineyards. The cold of May 13, 1895, wrought great wrought great havoc in the Chautauqua vineyards of New York, and forced the problem of how to manage frozen vines

upon the attention of growers. Fig. 62 shows the shoots of a grape vine as injured by the freeze. Acres of vineyards, which had made several inches of growth, were seemingly killed by the disaster.

[blocks in formation]

Fig. 62. Grape shoots ruined by the freeze of May, 1895.

The extent to which the vines had grown is shown by Fig. 63 (page 330). The spray upon the left shows the grapes of normal size (that is, from uninjured shoots) as they looked in midsummer. The central spray shows grapes which were produced from the second crop of flowers, which appeared after the

« ForrigeFortsæt »