- Bud: An undeveloped shoot.
- Fruit-bud: A bud in which a shoot bearing flowers originates.
- Wood-bud: A bud in which a shoot bearing only leaves originates.
- Latent bud: A bud which remains dormant for one or more seasons.
- Adventitious bud: A bud arising elsewhere than the normal position at a node.
- Eye: A compound bud.
- Main bud: The central bud of an eye.
- Secondary bud: The lateral bud of an eye.
Buds of different species of grapes vary greatly in time of opening as they do somewhat in varieties, so that the time the buds begin to swell is a fine mark of distinction. The angle at which the bud stands out from the branch is of some value in determining species. Differences in color, size, shape, position and amount of pubescence of buds must all be noted in describing grapes. The scales of the buds vary more or less in size and in thickness.
The flower.
Fig. 53. The grape flower. I. Opening bud showing the way in which the cap becomes loosened at the base. II. Diagrammatic illustration of grape stamens.
- Staminate: Having stamens and not pistils; a male flower.
- Pistillate: Having pistils and not stamens; a female flower.
- Diœcious: Said when the stamens are on one plant and the pistils on another.
- Polygamous: Said when flowers on a plant are in part perfect (having both stamens and pistils) while others are staminate or pistillate.
- Hermaphrodite: Said of a flower having both stamens and pistils.
- Fertile: Said of a flower capable of bearing seed without pollen from another flower.
- Sterile: Said of a flower without or with abortive pistils.
- Perfect: Said of a flower having both stamens and pistils.
- Imperfect: Said of a flower wanting either stamens or pistils.
- Peduncle: The stalk of a flower-cluster.
- Pedicel: The stalk of each particular flower.
The time of bloom is an easy mark of distinction between several species of grapes and helps to distinguish varieties in a species as well. Most species of grapes bear fertile flowers on one vine and sterile flowers on another and are, therefore, polygamous-diœcious. Sterile vines bear male flowers with abortive pistils so that, while they never produce fruits themselves, they usually assist in fertilizing others. Fertile flowers are capable of ripening fruits without cross-pollination. Vines with female flowers only are seldom found. In most species of the grape, plants with sterile flowers and those with complete flowers are found mixed in the wild state, but usually only the fertile plants have been selected for cultivation. Plants raised from seeds of any of the species, however, furnish many sterile vines.
The degree of fertility of blossoms is also a fine mark of distinction in species and varieties of the grape. Fertile vines are of two kinds in most species. The flowers on one kind are perfect hermaphrodites, while in the other kind the stamens are smaller and shorter than the pistil and eventually bent down and curved under. The two kinds of stamens are shown in Figs. [53] and [54]. These may be called imperfect hermaphrodites since they are seldom as fruitful as the perfect hermaphrodites unless fertilized from another plant. Examined with a microscope, it is found that self-sterile plants usually bear abortive pollen and that the percentage of abortive pollen grains varies greatly in different varieties. The upright or depressed stamen does not always indicate the condition of the pollen, since there are many instances in which upright stamens bear impotent pollen and occasionally the depressed stamens bear perfect pollen.