218 Biologie. — Morphologie etc. 



einen Vorteil davon zieht, ist fraglich. Das in Lipara-lucens-GaWen 

 des Schilfes lebende Pilzgeflecht steht wohl mit der Zersetzung der 

 abgestorbenen Gallentiere in Beziehung. — Die Lebensbeziehungen 

 zwischen nicht gallenbildenden Dipterenlarven und Pilzen hat 

 Rübsaamen 1908 zusammengefasst. Matouschek (Wien). 



Andree, A., Ueber die Ausläufer bei Ajuga- Arien. (4/5 Jah- 

 resber. niedersächs. bot. Ver. p. VI — VII. Hannover 1913.) 



Entgegen den Angaben in der Literatur ist nach Verf. die Art 

 der vegetativen Vermehrung bei den Arten Ajuga genevensis und 

 A. reptans nicht sehr verschieden: Erstere Art treibt aus den kur- 

 zen unterirdischen Rhizomen einzelne verdickte Wurzelfasern, die 

 ausläuferartig unter der Erdoberfläche wachsen und durch Spros- 

 sung neue Pflanzen bilden. Diese Organe werden als „Wurzel- 

 ausläufer" bezeichnet; mit der Ernährung der Pflanze haben sie 

 nichts zu tun. — Die zweite Art treibt unten am Stengel oberirdi- 

 sche Ausläufer gewöhnlicher Art. Matouschek (Wien). 



Cook, O. F., Brachysm, a hereditary deformity of cot- 

 ton and other plants (Journ. Agr. Res. Washington IIL 

 p. 387-400. 1915.) 



Brachysm is a term proposed by the author to designate the 

 shorthening of the vegetative internodes of plants. It is a heredi- 

 tary abnormality, indicating degeneracy, that has appeared in inde- 

 pendent mutative variations in many distinct families of plants, 

 including many cultivated forms. Brachitic variations are offrequent 

 occurrence in cotton, giving rise to the so-called "Cluster" and 

 "limbless" varieties, and afford unusually favorable opportunities 

 for learning the nature and physiological significance of such 

 variations." 



This remarkable abnormality, the shortening of the internodes 

 of the cottonplant is usually confined to the fruiting branches 

 without afifecting the main stalk or the vegetative branches. Bra- 

 chytic variations occur independently in different species and varie- 

 ties of cotton, and do not constitute a natural group with a common 

 origin. 



Brachytic varieties of cotton show other abnormalities of the 

 internodes, leaves, and involucral bracts. There is also an increased 

 tendency to abortion of the floral buds, and the blasted buds often 

 remain attached to the plant, because of the absence of well-diff"e- 

 rentiated absciss-layer at the base of the pedicel. Though brachytic 

 variations arise by mutative changes in the expression of characters 

 and show alternative Mendelian forms of inheritance, the}'' afford 

 no additional support to the general theories of mutation and Men- 

 delism as explaining evolution. Such variations represent reduced 

 specialisation or intermediate expression of characters and are 

 degenerative in nature. They are not to be considered as examples 

 of normal heredity or of the evolution of new characters. The 

 abnormalities of brachytic variations are analogous to those found 

 among hybrids and are likewise accompanied by tendencies to 

 sterility or abortion of buds. 



Brachysm is to be associated with other forms of intermediate 

 expression of characters, representing a general class of metaphanic 



