M. Decaisne on the Root of the Madder. 267 



were described from those of the female flower : the bractea, 

 present in both, has been complete!}' passed over; the calyx of 

 the male is stated to be three-parted, while it is six -parted ; and 

 the pubescence, which is present in the calyx of both sexes, 

 has been likewise omitted ; the bractea is likewise covered with 

 hair. 



River Quitaro, Lat. 2°. 50'. N., November 1837. 



XXIX.— On the Root of the Madder. By M. Decaisne. 



In the valuable ' Recherches Anatomiques et Physiologiques 

 sur la Garance/ lately published at Paris by M. Decaisne, 

 that gentleman gives the following interesting account of the 

 root. 



The roots of the Madder or Turkey red (Rubia tinctorum) 

 are of the form generally described as a branching root, for 

 though undivided when young, they shortly begin to ramify, 

 though the original shoot remains the thickest; their anatomy, 

 which I shall proceed in few words to describe and trace 

 through its several stages of growth, will explain their structure. 

 During the first days of germination, and while the plant has 

 no other leaves than its two cotyledons, the root is simple and 

 unbranched ; its upper part, immediately below the neck, 

 being covered with very slender fibrillae, which closely clasp 

 the grains of sand with which they may come in contact. If 

 the young root be cut horizontally across at this part, it will 

 be seen to consist, looking from the circumference to the 

 centre, of, first, a row of extremely small cortical cells, some 

 of which emit externally a very fine and simple prolongation, 

 constituting the above-mentioned fibrillae, in the same way 

 as the epidermal tissue of leaves gives rise to hairs. After 

 this row of cortical cells comes a thicker or thinner layer of 

 cellular tissue, whose divisions diminish in size as they ap- 

 proach the centre, while the innermost part is almost con- 

 founded with the fibrous tissue which surrounds the vessels 

 occupying the whole middle of the root. The vertical section 

 of a young rootlet (if it may be so termed) exhibits the cor- 

 tical cells arranged in nearly regular longitudinal series, 

 slenderer than the others ; then those which compose the 

 fleshy portion in series which become more and more regular 



