16 NATURAL HISTORY OF PLANTS. 
special formations that give the plants of this family a particular 
character. In the wood is found beside the medullary rays, formed 
of a single row of cells, fibro-vascular bundles, representing in trans- 
verse section concentric circles of islets. Each bundle comprises 
externally cells; more internally fibres, and quite inside, vessels. 
These same bundles are repeated in the pith, composed and arranged 
in the same way—that is to say, disseminated as in a monocotyle- 
donous stem.’ The general organization is the same in Oxybaphus 
and Ifrabilis. But in the former, the bundles scattered through the 
woody mass in Pisonia “ tend to, approach, and join each other. The 
general woody mass in which they are plunged is already a little less 
homogeneous, and the woody fibres less perfect.” And in dfrabilis 
the bundles remain nearly the same; the fibres of the general woody 
mass have quite the character of young fibres in process of formation 
from the primitive elongated cell.’ In all three the pith is partly 
filled with isolated fibro-vascular bundles. In several genera (J/ira- 
bilis, Boerhaavia, Oxybaphus, Pentacrophys, §c.) the roots rapidly 
take the conical form of a swollen tap-root, with fleshy concentric 
layers in which the juices collect; it is often gorged with starch and 
with certain active principles. 
These principles give to the roots of several Nyctaginacee properties 
sometimes tolerably powerful,’ which led the ancients to derive from 
this family several evacuant drugs, such as Jalap. The production 
of this was formerly ascribed to the common Marvel of Peru or 
Mirabilis Jalapa' Li. (figs. 1-10), and to JZ. dichotoma L.* and longi- 
fora Lf It is now known that they only yield a root of spurious 
Jalap, the section polished blackish or greyish, marked with con- 
centric striæ, “hard, compact, very heavy, with a faint nauseous 

1 Disposition which introduces into the woody 
mass the elementsof cortical layers. REGN. loc. cit. 
2 Mirabilis, he says, is destitute of true liber, 
3 GuiB, Drog. Simpl., ed. 6, ii. 444.—Enpt., 
Enchirid., 194 —Linvu., Fl. Med., 365; Veg. 
Kingd., 507,—Rosrentu , Sym. Pl. Diaphor., 
226, 1111. 
4 See p. 1-4. 
5 Spec., 252 (nec GARER.).—PLENK, Off, 
t. 139.—Cnois., Prodr., 428, n. 2.—Jalapa 
officixarum Marvin, Cent., 1, t. 1.—Nyctago 
dichotoma J, (vulg. Fleur de quatre heures). 
5 Spec., 252.—PLENK, Off. t. 138.—CHors > 
Prodr., n. 5.—Jalapa longiflora Mæœxcx.— 
Alzoyati HERNAND., Mexic, 170, fig. 2.— 
Nees D’Esrnprck (Pl, Medic., Suppl., t. 33), 
believed that this species supplied the “7acine 
de Mechoacan gris” or “radix Metalistæ” of the 
apothecary, which is a powerful drastic. IZ, 
suavolens (H. B. K., Nov. Gen. et Spec., ii. 
213); and I. odorata of gardens [in Linnea 
(1888), 75], regarded in Mexico as good re- 
medies in diarrhoea and rheumatism, are ascribed 
in Prodromus to this species. 
