Floristik, Geographie, Systematik etc. 207 



of these is so characteristic and distinct from that of. Cypripediuni , 

 that it would require very little time to identify them. 



Theo Holm. 



Holm, T., Medicinal plants of North America. 14. Gelsemiunt 

 sempervirens Ait. (Merck's Report XVII. p. 86—89. f. 1 — 17. April 

 1908.) 



The dried rhizome and roots are yellowish and of a somewhat 

 narcotic odor, and a bitterish taste; they contain gelsemic acid, 

 gelsemine and gelseminine, which are alkaloids. What is called rhi- 

 zome is, however, merely the basal rooting portion of the vine, 

 hence better to be determined as a pseudo-rhizome. Characteristic 

 of the roots is the presence of a non-contractile exodermis, and the 

 yellow matter contained in some of the tissues, besides that the 

 activity of the pericambium begins later than the development of 

 secondary mestome. In the stem above ground the stele is directly 

 covered by an endodermis and a collenchymatic pericycle; the 

 mestome-strands are bicollateral, there being four large Strands of 

 leptome located in the periphery of the pith. In the basal, partly 

 subterranean internodes we find a very different arrangement of 

 the tissues, since endodermis and the stereomatic pericycle are located 

 in the middle of the cortex, a structure that has also been observed 

 in Strychnos. The leaf-structure is bifacial with a palisade-tissue of 

 normal structure, There is no other mechanical tissue in the leaf 

 than a few hypodermal layers of collenchyma on the leptome-side 

 of the midrib, and a slightly stereomatic pericycle. The stomata 

 have one pair of subsidiary cells, and are confined to the dorsal 

 face of the blade. Theo Holm. 



Holm, T., Method of hibernation and vegetative reproduc- 

 tion in North American species of Stellavia. (American Journ. 

 of Science. IV. 25. p. 315—322. f. 1-6. April 1908.) 



In the North American species of Stellaria s. s. (not including 

 Malachimn and Cherleria) the primary root is only of short duration, 

 but becomes replaced by secondary roots developing from the basal 

 nodi of the stem above ground or from the rhizome. Very charac- 

 teristic of several of these high alpine or arctic species is the ability 

 of the stem above ground to remain active for more than one season, 

 beside that some of these are, moreover, provided with true rhi- 

 zomes. In S. pubera Michx. tv^ro kinds of aerial shoots are developed: 

 floral and vegetative; of these the latter persist and become closely 

 appressed to the ground during the autumn. They remain alive 

 throughout the winter, and new shoots in pairs develop from their 

 leaf-axils in the follow^ing spring; then the mother shoot becomes 

 broken at the joints, and gives rise to new, independent individuals. 



In 5. longipes Goldie the aerial stems remain active throughout 

 the winter, and buds are developed in the axils of the withered 

 leaves. During the following spring these buds produce shoots, which 

 remain vegetative for a season or two in the arctic regions, Avhile 

 in the alpine they develop an inflorescence in the first season. The 

 rhizome of this species has long, slender stolons with minute scale- 

 like leaves, and the internodes are stretched. The high alpine 5. 

 umbellata Turcz. shows the same peculiarity in regard to the per- 

 sisting stems above ground, but in this species the internodes of 



