136 MORPHOLOGY, ETC., VASC. PLANTS [BoT. Absts., Vol. IX, 



870. Meyer, Fritz JuRGEN. Das Leitungssystem von Equisetum arvense. [The conduct- 

 ing system of Equisetum arvense,] Jahrb. V/iss. Bot. 59: 263-286. Fig. 1-7. 1919.— 

 The author describes the structure and arrangement of all the elements at the node of 

 the aerial sterile stem, the relative positions of protoxylem and meta.xylem strands and of 

 the phloem as they pass through the nodal wood ; the method of insertion of the leaf and branch 

 traces; the relative positions of the carinal holes in successive internodes and the arrangement 

 of the conducting bundles to conform to these; the path of the conducting system through 

 the nodes and internodes of the rhizome, tuber, leaf of the rhizome, secondary roots, branch 

 roots, sterile stem and its branches and leaves, and the fertile stem and its leaves and cone; 

 the connection between the parts of the system in passing from one organ to another, and the 

 size of the xylem strands both in micromillimeters and in number of tracheids. He discusses 

 the variations in bundle size in different regions of the plant; and the function, size, and 

 formation of the carinal hole. — J . P. Poole. 



871. MoBius, M. Die Entstehung der schwarzen Farbung bei den Pfianzen. [The origin 

 of black coloration in plants.] Ber. Deutsch. Bot. Ges. 38: 252-2G0. 1920. — The author calls 

 attention to the fact that black coloration in plants is generally not the result of the presence 

 of a truly black pigment but of blue, red, or brown colored substances which, as well as cer- 

 tain histological factors, may produce the same optical effect as would a black pigment. He 

 then presents a classification of the causes of black coloration. Under each of the many 

 headings and subheadings notes are given, and plants are named which illustrate the par- 

 ticular sort of coloration under discussion. — R. M . Holman. 



872. Neger, F W., UND Th. KuPKA. Beitrage zurKenntnisdesBauesundderWirkungs- 

 weise der Lentizellen. I. [Contributions to a knowledge of the structure of lenticels and of 

 the manner in which they function.] Ber. Deutsch. Bot. Ges .38:141-149. Fig. 1-6. 1920. — 

 This paper is concerned with the lenticels of conifers, particularly Larix, Pseudolarix, Cedrus, 

 and Chamaecyparis. The tissues which may be found in lenticels of conifers are classified by 

 the authors as: (1) "Choriphelloid," making up the greater part of the lenticels and loose in 

 texture with large intercellular spaces; (2) "Porenkork," strips consisting of a few layers of 

 compact brownish cells generally containing small crystals and with very short radial diame- 

 ter; (3) "Sklerophelloid," lens-shaped groups of compact cells with strongly thickened walls; 

 and (4) fragments of the primary cortex. A key to the commoner species oi Larix is given, 

 based on the anatomy of the lenticels, and also a similar key by which Cedrus Libani, 

 C. atlantica, and C. Deodara may be distinguished. Of the 5 species of Chamaecyparis, 

 C.pisifera alone lacks lenticels. The other species of the genus, as well as Thuja and Juniper us, 

 and presumably most other Cupressineae, have lenticels of a new type. The center of the 

 lenticel in these forms consists of a large mass of compact "Porenkork," the cells of which are 

 filled with dark brown contents. Exposure of stems to dilute ammonia gas and subsequent 

 examination of the cortical tissue underneath the lenticel for evidence of injury to the living 

 tissue shows that the central mass of "Porenkork" is impermeable to the gas, which, however, 

 finds easy entrance through thin walled cells without brown contents which lie on either side 

 of the "Porenkork" mass. — R. M. Holman. 



873. Oakley, R. A., and Morgan W. Evans. Rooting stems in timothy. Jour. Agric. 

 Res. 21 : 173-178. PI. 39-40. 1921. — There are 2 distinct types of underground rooting stems 

 of Phleuia pratense. One type develops when the shoot that produces the new plant is 

 covered with soil early in its growth. In such cases, some of the short internodes at the 

 base of the shoot elongate, thereby pushing the shoot to the surface of the soil. Roots 

 spring from the nodes between these elongated internodes. The other type develops 

 when growing culms are covered with soil. Buds that sometimes form on the culms of 

 such plants frequently develop into shoots and ultimately into independent plants. In 

 this case the culm becomes an underground rooting stem. — Aerial rooting stems in timothy 

 are not common in the United States. They may be formed when weak or decumbent 

 plants come in contact with the soil. This character is not of varietal significance. 



