34 T. Holm — Chionophila Benth. 



lariaceae nothing is said about the root-structure. With 

 respect to C. Jamesii the structure is of special interest, 

 since I observed the development of cork to take place in 

 the peripheral stratum of the cortex, the stratum border- 

 ing on the exodermis {^g. 5), and, as we remember, De 

 Bary records only two cases of cork being developed in the 

 peripheral strata of the root-cortex, namely in Clusia and 

 Bignonia capreolata ;* since then Olivier detected a simi- 

 lar structure in Artanthe pothifolia, Jasminum humile, 

 and Ruyschia Souroubea f to these may be added Tecoma 

 radicans and Cephalanthus occidentalis.^ 



There was no primary root in any of the specimens, 

 which I collected, and the root-system consisted merely of 

 several strong, secondary roots developed from the sub- 

 terranean part of the stem; these roots were sparingly 

 branched, and only slightly hairy. Inside the epidermis 

 is a thinwalled, contractile exodermis (Ex. in ^g. 5), cov- 

 ering an open cortical parenchyma of about twenty layers, 

 with no starch or crystals; a phellogen (Ph.) arises, as 

 stated above, in the peripheral stratum. Inside the cor- 

 tex follows a thinwalled endodermis (End. in figure 6), 

 surrounding the pericambium (P), in which tangential 

 cell-divisions appear outside the protohadrome, being the 

 only indication of secondary increase in the young roots. 

 The roots are pentarch with five strands of leptome alter- 

 nating with five short vajs of hadrome. The center of 

 the stele represents a relatively broad, thinwalled pith 

 without starch. 



As the roots grow older the cortex collapses, and some 

 few secondary vessels develop on the inner flank of the 

 leptome. The main stem, which is terminated by the ro- 

 sette of leaves, shows the following structure. The upper 

 internodes are cylindric, glabrous and smooth. A thin 

 cuticle covers the slightly papillose epidermis, and the 

 cortical parenchyma is homogeneous, of about twenty 

 strata with distinct intercellular spaces, and containing a 

 little starch. There is no endodermis, and no pericycle, 

 but a band of isolated, small strands of leptome, and a con- 

 tinuous band of cambium, inter- as well as intra-fascicu- 



* De Bary, A, Vergleichende Anatomie, p. 563. 1877. See also Van 

 Tieghem, Ph. Eecherches sur la symetrie de structure des plantes vasciilaires. 

 (Ann. sc. nat. Bot. Ser. V, 13. p. 258. 1870.) 



^ Olivier. Eecherches sur 1 'appareil tegumentaire des racines, ibid. Ser 

 VI, 11. p. 124. 1880. 



«Holm, Theo. Eubiaceae; Bot. Gaz., (vol. 43, p. 155). 1907. 



