OF ORNAMENTAL ANNUALS. 
43 
CHAPTER IV. 
UMBELLIFEBJE. 
Essential Character. —Flowers usually disposed in umbels. Calyx superior. Disk epigynous, very thick, in two or more pieces. Carpels 
always 1-seeded. Stems usually hollow.—( Lindl.) 
GENUS I. 
DIDISCUS, Dec. THE DIDISCUS. 
Lin. St/st. PENTANDRIA DIGYNIA. 
1.—DIDISCUS CiERULEUS. Dec. THE AZURE DIDISCUS. 
Generic Character. —Margin of the calyx obsolete. Petals oval, 
bluntish, imbricate in aestivation. Fruit didymous, emarginate at the 
base. Mericarps rough from pilose strigae, 5-ribbed, two middle ribs 
approximating the commissure. Involucrum of many leaves, which arc 
concrete at the base.—(G. Don.) 
Synonymfs —Trachymene cyanaea, Cunn.; T. caerulea, Graham ; 
Rugelia cyariEoa, Rehb. 
Engravings. —Bot. Mag. t. 2875 ; Bot. Reg. t. 1225 ; and our 
fig. 3, in plate 7. 
Specific Character- Plant hairy; leaves petiolate, 3-parted; 
having the partitions 2-3-clcft, and the lobes 2-3-toothed; umbels 
simple, on long peduncles; involucrum of many leaves, when young 
reflexed.—(G. Don.) 
Description, &c.— A very beautiful half-hardy annual, with azure blue flowers, produced in umbels. When 
the flowers drop, the little stalks on which they grew twist inwards and enclose the seed as in a cage. The leaves 
are lobed and large, and the stem erect and rather tall. This beautiful plant is a native of New Holland, and 
was introduced in 1827. It was first raised in England in the Horticultural Society’s Garden, from seeds sent 
home from Sydney by Mr. Charles Frazer. It is frequently called Trachymene caerulea in the seed-shops, from 
its having been thus designated in the Botanical Register for 1829. In the first volume of the Ladies’ Botany , 
however, published in 1834, Dr. Lindley has called it Didiscus caerulea (p. 32). It must be cultivated as a half- 
hardy annual; and if the seeds are sown in a hotbed in March, they will be ready for planting out in June, and 
will flower in August or September, and continue beautifully in bloom till November, or till they are killed by 
the frost. “ If sown in August, the plants should be potted in small pots in October, and kept rather dry than 
otherwise during the winter. Thus treated, and removed into larger pots in spring, they will flower beautifully 
in a frame or greenhouse, and much better than in the open ground. These plants should never be headed down, 
as their flowers are produced at the extremity of the main stem and branches.”— D. B. If kept in the green¬ 
house, and constantly changed into larger pots as they grow, they will become very fine, and flower beautifully ; 
and our drawing was made from a plant in the nursery of Messrs. Osborn at Fulham, which had been treated 
in this manner ; but we have since seen some equally fine specimens growing in the open air. 
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