160 



IRIDACE.E. 



[Endogens. 



embryo 



Fig. CXI. 



spheroidal, angular, oblong, or winged ; albumen horny, or densely fleshy 

 inclosed within it, the radicle being uniformly next the hilum. 



This Order differs from that of Amaryllids essentially, in being triandrous, with the 

 anthers turned outwards ; from Orchids, to which it approaches nearly in some respects, 

 in not being gynandrous ; in the nature of the seeds and placentae, in all the anthers 



being distinct ; from Gingers and Arrowroots 

 the three perfect stamens divide it, indepen- 

 dently of the structure of the leaves, which 

 are extremely different. Blood-roots, which 

 are often triandrous with equitant leaves, 

 have the anthers bursting inwardly, and 

 when triandrous their stamens are opposite 

 the petals. The Iris represents the general 

 structure of the Order ; but a departure 

 from the form of perianth found in that ge- 

 nus takes place in Crocus, the flower of 

 which is extremely like that of Gethyllis and 

 Oporanthus among Amaryllids on the one 

 hand, and of Colchicum among Melanths on 

 the other ; the latter is known by their supe- 

 rior triple ovary. The dilated stigma found 

 in Iris is characteristic of only a part of the 

 Order ; in Crocus the stigma is rolled up 

 instead of being spread open, and in many 

 genera it is absolutely thread-shaped. Brown 

 observes, that Burmannia appears at first 

 sight to agree with Irids, especially in its 

 equitant leaves, coloured superior trian- 

 drous perianth, and 3 dilated stigmas ; it 

 cannot, however, be united with them, on 

 account of its fertile stamens being opposite the inner segments of the perianth, and 

 alternating with an equal number of sterile ones, because of the transverse dehiscence 

 of the anthers, and also the structure of the seeds. In Xyris some resemblance with 

 this Order is discoverable, especially in the disposition of the leaves, the triandrous 

 flowers, and anthers turned outwards ; but that genus is very distinct in its free peri- 

 anth, the outer segments of which are glumaceous, and the inner distinctly petaloid, in 

 the ungues bearing the stamens at their apex, in the sterile alternate stamens, and 

 especially in the structure of the seed. — Prodr. 302. The whole Order is greatly in 

 want of a good critical examination ; but much caution is required in forming the 

 genera, especially in deriving characters from the seeds, for they are both round, and 

 fleshy, and thin, in the genus Iris. 



The Irids are principally natives either of the Cape of Good Hope, or of the 

 middle parts of North America and Europe. A few only are found within the tropics, 

 and the Order is generally far from abundant in South America, if compared with the 

 numbers that exist at the Cape. The genera Marica and Morsea appear to occupy the 

 same station in hot climates that Iris, a closely related genus, does in cooler latitudes. 

 Crocus, among the most conspicuous of the Order, occurs only in Europe and Asia. 

 None of the Cape or New Holland forms appear in America. 



More remarkable for their beautiful fugitive flowers than for their utility. The 

 rhizome of some of them is slightly stimulating, as the violet-scented Orris root, the pro- 

 duce of Iris Florentina. Various species of Sisyrinchium, Ferraria, Libertia, and the 

 Irises pseud-acorus, tuberosa, versicolor, and verna, are used as diuretics, purgatives, and 

 emetics, but some of them are apt to produce distressing nausea like sea-sickness, with 

 a prostration of strength. The substance called Saffron is the dried stigmas of Crocus 

 sativus ; its colouring ingredient is a peculiar principle, to which the name Polychroite 

 has been given ; it possesses the properties of being totally destroyed by the action of 

 the solar rays, of colouring in small quantity a large body of water, and of for min g blue 

 and green tints when treated with sulphuric and nitric acid, or with sulphate of iron. 

 In moderate doses this substance stimulates the stomach, and in large quantities excites 

 the vascular system. Moreover it seems to have a specific influence on the cerebro-spinal 

 system, as it affects, it is said, the mental faculties, a result which De Candolle considers 

 analogous to that produced by the petals of certain odorous flowers. " In modern prac- 

 tice it is little used, except as a colouring ingredient ; on the Continent it is employed 



Fig. CXI. — 1. Spathe and flowers of Rigidella iminaculata ; 2. the petals, stamens, &c. of it ; 3. 

 cross section of the capsule of Fardanthus Chinensis ; 4. a perpendicular section of its seeds. 



