558 Angewandte Botanik. 



interior part of the cortical parenchyma, and the latter are especially 

 frequent around the secondary stereome. These peculiarities were, 

 also, observed in the stolons, with the exception that there is no 

 collenchyma, thus the cork develops from ordinary parenchyma 

 beneath epidermis. 



The leaves are bifacial, and the stomata lack subsidiary cells; 

 glandulär hairs were observed, and such occur, also, on the young 

 stem. The palisades are lobed, and there is no other mechanical 

 tissue than a little l^podermal collenchyma above and below the 

 midrib. We find in the midrib a Single, collateral mestome-strand, 

 destitute of stereome. No secreting ducts, and no cells with crystal- 

 line sand were observed in the leaf-blade. while such occur in the 

 petiole, the former in the pericycle, the latter in the pith. 



Theo Holm. 



Holm, T., Medicinal plants of North America. 33. Prunus 

 serotina Ehrh. (Merck's Report XVIII. p. 287-290. fig. 1—7. 

 Nov. 1909.) 



The bark of Prunus serotina Ehrh. (P. virginiana Miller not 

 Linne) is official in Great Britain and the United States; in the 

 former country it is called "Pruni virginianae cortex". Although 

 the bark is obtained indiscriminately from all parts of the tree, 

 that of the roots is deemed the most active. It has an astringent, 

 aromatic and bitter taste. Hydrocyanic acid is most abundant in 

 the roots, and more so in the twigs than in the trunk. 



The bitter principle, which appears to be the fluorescent sub- 

 stance has the character of a glucoside, and crystallizes in colorless 

 needles. A volatile oil and hydrocyanic acid may be obtained from 

 the leaves, and may be substituted for the Cherry-Laurel- water. 

 The drug is adapted to the treatment of diseases in which debility 

 of the stomach or of the System is united with general or local 

 irritation; it is much employed in the hectic fever of scrofula and 

 consumption. 



The morphology of the plant is discussed and figured. The seed- 

 ling has a long, primary root, hypogeic cotyledons, and a long 

 epicotyl. The first leaves are opposite and lack glands on the petio- 

 les. We find in the root a "r^seau de soutien" in the cortical paren- 

 chyma just outside endodermis; moreover are noticed in the secon- 

 dary cortex scattered Strands of stere'i'ds and sclereids. In regard to 

 stem-structure Solereder records a pericycle of stereomatic fibers 

 and sclerotic cells from Pomeae e. g. Crataegus , Stranvaesia, Cha- 

 maemeles, Osteomeles and Sorbus, but such I observed also in this 

 species of Prunus. But otherwise the origin of the cork , the struc- 

 ture of the cortex, of the stele, and the pith shows nothing of 

 special interest, when compared with that of the other woody Rosa- 

 ceae according to Solered er's description. 



The leaves are bifacial with cuticular crests about the midrib; 

 the stomata lack subsidiary cells. There are two to three layers of 

 high palisade-cells and a very open pneumatic tissue. Large crystals 

 of calcium Oxalate abound in the hypodermal layers of the latter 

 tissue, but are scarce in the palisade-cells. The midrib contains a 

 Single, collateral mestome-strand with an interrupted stereomatic 

 pericycle, a structure that recurs in the petiole. While the leaves 

 of the tree are held in a horizontal position, the leaves of the seed- 

 ling are erect, but nevertheless their structure is identical except 



