Morphologie, Teratologie, Befruchtung, Cytologie. 37 



growth, not being found in the young ray. In young roots of/'/wMS 

 the phloem shows certain cells which are essentially short sieve 

 tubes occurring in groups in a radial plane. When such a group 

 occurs in vertical contact with a medullary ra3% cambial activity is 

 localized at the edge of the ray, producing a border consisting of 

 sieve cells, which are the errect cells found in the mature phloem. 

 There are some variations from this mode of origin. 



In young roots and stems marginal cells appear in the phloem 

 earlier than in the xylem. In Abtes, marginal cells have disappeared 

 from the xylem but not from the phloem. This and other observa- 

 tions indicate that the phloem is a more conservative region than 

 the xylem. Charles J. Chamberlain (Chicago). 



Hammarlund, C, En knoppvariation hos Crataegus monogyna 

 Jacq. (Bot. Notiser 1914. p. 17—23. 2 Textfig. Deutsch. Resume.) 



Verf. beschreibt eine von ihm bei Crataegus monogyna gefun- 

 dene Knospen Variation, deren ßlatttypus sich in einigen Hinsichten 

 dem Typus von C. oxyacantha nähert. Nebenblätter und Dornen 

 fehlen bei der Variation. Die Winterknospen sind bei dieser ge- 

 spitzt, beim normalen Zweige mehr abgerundet. Die Endknospe 

 ist beim letzteren bedeutend grösser als die Seitenknospen, während 

 bei der Variation alle Knospen derselben Grösse sind. 



Die Blätter der normalen Zweige sprossen etwa drei Wochen 

 früher aus, und der Blattfall tritt um zwei Monate später ein als 

 bei der Variation. Bemerkenswert ist, dass der im übrigen nor- 

 male Zweig in dieser Beziehung abweichend ist, während die 

 Variation in diesem Falle sich wie C. monogyna verhält. 



Die Entstehung und Natur dieser Knospenvariation wird vom 

 Verf. experimentell geprüft werden. 



Abgebildet werden Serien von Blättern sowie Zweige der nor- 

 malen Form und der Knospenvariation. 



Grevillius (Kempen a. Rh.). 



Holm, T., Phryma leptostachya L,, a morphological study. 

 (Bot. Gaz. LVI. p. 306—317. PI. 8—10. 1913.) 



The seedling and the mature plant are described, the external 

 as well as the internal structure, illustrated by nineteen tigures. 

 Characteristic of the seedling- stage are the hypogeic cot3iedons 

 which remain inclosed within the seed, surrounded by the thin 

 pericarp; furthermore the very short hypocotyl and primary root; 

 buds are developed in the axils of the cotyledons, and the first 

 internode above cotyledons, the epicotyl, is long, erect, cylindric 

 and glabrous. In the mature plant the subterranean stem-portion 

 represents internodes; a few overwintering buds, and a secondary 

 System of roots, the primary having faded away at an early stage. 

 Two types of roots occur in Phrym.a viz.: nutritive, represented 

 by the primary; and a combination of contractile and storage roots. 

 as shown by the secondary with contractile exodermis and starch 

 deposits in cortex and pith. A thinwalled endodermis was observed 

 throughout the stem, while the so-called pericycle is relatively poorly 

 developed; as a closed sheath of stereids this tissue occurs only in 

 the inflorescence, when the fruits have matured; in the pseudo- 

 rhizome it is represented merely by parenchyma with isolated 

 Strands of stereome, while in the other internodes it is either uni- 



