UKTIOACE.B. 



583 



as artists' oil. Groaophora tinotoria supplies a purple dye called 

 Turnsole, ■wMoli becomes blue on the addition of ammonia. The 

 seeds of a few species of Aleurites, Anda, and Omphalea, are edible. 



Order 163. — UeticacE/B, the Nettle Fsimily. (Apet. Diclin.) 

 Flowers unisexual (figs. 824, 826), usually in cymes or polygamous, 

 or collected into catkins or heads. Perianth usually divided (fig. 

 826).. Stamens definite, inserted into the perianth ; filaments some- 

 times curved in aestivation (fig. 825). Ovary superior (figs. 827, 



Fig. 825. 



Pig. 827. 



Fig, 828. 



Fig. S29. 



-828), 1-celled; ovule solitary, erect (fig. 828), orthotropous ; style 

 simple or with a capitate or penicillate stigma (fig. 828). Fruit an 

 achene (fig. 460, p. 257), or a drupe (fig. 460, p. 257), naked or sur- 

 rounded by the persistent, sometimes accrescent, perianth. Seed soli- 

 Figs. 824-830. Organs of fructification of Urtica urens, to illustrate the natural order 

 Urticacese. Fig. 824. Bud of the male flower, viewed from above. Fig. 825. Stamen 

 taken from the feud of the male flower, with the elastic, incurved iUament, and the anther 

 bent down before dehiscence. Fig. 826. Male flower expanded, c, Perianth with four 

 divisions, e e e e, Four hypogynous stamens, thrown back by the elasticity of the fila- 

 ments, with the anthers burst, pr, Abortive rudiment of the central pistil. Fig, 827. 

 Female flower, c. Perianth with four unequal segments, the two exterior ones being very 

 small. 0, Unilocular ovary, s. Sessile stigma. Fig. 828. Pistil cut vertically, to show 

 the direction of the erect ovule, o. p, Parietes of the ovary, s. Stigma. Pig. 829. Seed 

 cut vertically, parallel to the cotyledons, i. Integument (spermoderm). h, Hilum, p, 

 Perisperm. e. Embryo straight, with the radicle superior. Fig. 830. Seed cut perjien- 

 <licularly to the cotyledons, t, Integument. %, Hilum. j), Perisperm, e. Embryo. 



