230 The Pedigree Families. 



second generation in 1898 and a third in 1899, both of 

 annual individuals. Both generations were absolutely 

 constant and exhibited no signs of reversion ; but con- 

 sisted only of a few individuals on account of the paucity 

 of the harvest which each generation gave (86 in 1898 

 and 36 in 1899). 



III. O. rubrinervis. A beautiful species w^hicli often 

 has red veins on the leaves and broad red stripes on the 

 calyx and fruit. Markings of this kind do, it is true, 

 occur sometimes on 0. Lamar ckiana, but they are never 

 so pronounced that tlieir possessors could possibly be 

 mistaken for O ruhrinervis. The flowers are somewhat 

 larger and a rather darker yellow. The stem, especially 

 in annual cultures, is generall}^ shorter than that of La- 

 marckiana and suffused with red. The species cannot 

 as a rule be recognized in the very young rosette stage '} 

 in fact not till the plant has 10-20 leaves, or later if the 

 plants are grown too close together. Ruhrinervis was 

 therefore not detected until after the latas and nanellas 

 had been identified and removed. It is then easily rec- 

 ognizable by its narrow and long leaves with red veins, 

 and by its vigorous habit. 



A very peculiar feature of this species is the brittle- 

 ness which characterizes the annual forms to a much 

 greater extent than the biennial ones. The stem and 

 leaves can be broken by a moderately hard blow. If such 

 a blow is administered to the flowering plant from above, 

 the stem splits into several pieces with perfectly smooth 

 surfaces of fracture. The cause of this is the extra- 

 ordinarily slight development of the bast-fibres which 

 however are not entirely lacking as microscopical investi- 



' The distinguishing characters have since been found in verv 

 young seedlings (Note of 1908). 



