350 Angewandte Botanik. 



on both faces of the leaf-blade, but the chlorenchyma shows a ty- 

 pical dorsiventral structure with a ventral palisade-tissue; the midvein 

 contains a Single arch of mestome with a barely distinguishable 

 Support of stereome. In the upper part of the petiole is an oval based 

 of seven separate, collateral mestome Strands embedded in a large 

 green parenchyma with ducts and numerous aggregated crystals. 



Theo Holm. 



Holm, T., Medicinal Plants of North America. 92. Ana- 

 nassa sativa Lindl. (Merck's Report 24 p. 192-194. f. 1 — 18.1915.) 



Some years ago V. Marcano discovered that the juice ofpine- 

 apple has the power of digesting proteid vegetable and animal 

 substances. Furthermore R. H. Chittenden found that the fresh 

 juice is a very constant and powerful digestant of albuminous mat- 

 ters; that the ferment, bromelin, is decidedly active in the presence 

 of either acide or alkaline carbonates, but is most energetic in ven 

 tral Solution. The plant is described and figured. The roots have a 

 thinwalled exodermis bordering on a closed sheath of about 15 

 layers of stereids, sclerei'ds and thickwalled parenchyma. The cortex 

 proper is thinwalled, and breaks down so as to form wide lacunae. 

 The endodermis is thickwalled, a typical U-endodermis, and the 

 pericambium is of two layers, nowhere interrupted by the proto- 

 hadrome-vessels. In the stele is a very broad, central group of 

 thickwalled conjunctive tissue. None ot the roots were observed to 

 remain enclosed within the stemcortex as is otherwise characteristic 

 of several generic of the Bromeliaceae as described by Alfred 

 Invergensen (Bot. Tidsskr. 3. Vol. 2. p. 144. Copenhagen 1877 — 

 1879). The leaf-structure agrees in most respects with that of the 

 epiphytic genera viz. the huge waterstorage tissue with spiral 

 thickenings; the very open pneumatic tissue, and the dorsal location 

 of the palisade-tissue, beside the presence of a double hypoderm. 



Theo Holm. 



Holm, T., Medicinal plants of North America. 93. Vanilla 

 planifolia An dr. (Merck's Report. 24. p. 212-215. f. 1—16. Sept. 1915.) 

 The plant is figured and described. The aerial roots have no 

 velamen, but several strata of pericambium, the cells of which are 

 thickwalled outside the leptome; a large conjunctive tissue occupies 

 the Center of the stele. The aerial stem has no endodermis, but a 

 closed sheath of a few layers of stereome, inside of which is a 

 large parenchyma traversed by many scattered, collateral mestome- 

 strands all supported by arches of stereome on the leptome-side. 

 The leaf-structure is dorsiventral so far as concerns the location of 

 the stomata, but the chlorenchyma lacks a palisade-tissue; the entire 

 chlorenchyma is very thick and consists of about eighteen strata 

 of roundish cells. All the veins are thin, arranged in a Single plane, 

 and embedded in the chlorenchyma; they are surrounded by thin- 

 walled parenchyma-sheaths, and are supported by arches of stereome. 

 The correlation between the root-structure and the leaf-structure is, 

 thus, well illustrated by Vanilla, the absence of a velamen in the 

 roots, and the presence of a large water storage-tissue in the leaves. 



Theo Holm. 



Holm, T., Medicinal plants of North America. 94. Maranta 



arundmacea L. (Merck's Report 24. p. 238— 241. f. 1—14. Oct. 1915.) 



The rhizome gives rise to two kinds of buds, some thatdevelop 



