This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
When flowers occur singly at the end of an axis, as in the Tulip, it is terminal and solitary; and when only one flower is produced in the axil of an ordinary leaf it is termed axillary and solitary. More often two or any larger number of flowers are associated together on a floral axis, with or without bracts at the base of the individual flower stalks, and such an association is termed an "inflorescence". The floral axis shows greater variation in the modes of branching than the ordinary stem. The monopodial or indefinite form is seen in the Wallflower, Rocket, Lily of the Valley (fig. 43), and Laburnum, in each of which the inflorescence is a raceme. The lowest flower is the oldest and first to open, and is succeeded by others in centripetal order, and each is furnished with a stalk of its own. The spike is also monopodial, and differs from the raceme by the absence of stalks to the flowers, as in Orchis and Verbena. The corymb is a form in which the lower flower stalks are long, so as to bring the flowers all to the same level, as in Star of Bethlehem. The umbel has its flower stalks all of the same length, and arising from one point, as in the garden Polyanthus, Cowslip, and Cherry. The compound umbel is seen in the Carrot, Parsnip, Parsley, and Celery. The first or primary flower stalks do not bear flowers, but give rise to secondary umbels of stalked flowers. The capitulum (fig. 44) is seen in the Daisy, Dandelion, and Marguerite. It consists of an aggregation of small flowers or florets, in a head, surrounded by numerous bracts. The outer florets are the oldest and first to open, as in other indefinite inflorescences. The panicle is a branching inflorescence, the branches of which may be in racemes, as in the Cabbage, or in spikes, as in Beet.
Fig. 43. - Racemose Inflorescence - Indefinite.
A DUTCH HYACINTH NURSERY.
A BULB FARM AT WISBECH, CAMBRIDGESHIRE (Mr. J. W. Cross).
DUTCH AND ENGLISH HYACINTH FARMS.
Sympodial or definite inflorescences are fairly numerous, but all are characterized by the axis terminating in a flower which is the oldest and the first to open, but the stalk soon ceases to lengthen, and all the other flowers are produced on branches which spring from a point lower down and soon overtop the primary axis. The various forms of definite inflorescence are termed cymes. The dichasial cyme is seen in the Stitchworts (Stellaria), Lychnis, and others, in which both lateral branches are developed equally, each terminating in a flower (fig. 45). The scorpioid cyme is seen in Forget-me-not and Heliotrope. The corymbose cyme is that in which the branches all terminate on the same level, and the Sweet William comes near this type. The panicled cyme may be seen in the herbaceous Spiraeas.