1920 



A TEXTBOOK OF THEORETICAL BOTANY 



Fig. 1845. — AntlnliliiHin nin/iis. Flowers in longitudinal 

 section showing how the entrance is forced open by 

 humble bees. 



present on the lower lips of the flowers. In Linaria (Fig. 1846) (Toadflax) 

 nectar is secreted at the base of the ovary and stored in the spur. In 

 this genus should pollination fail, cleistogamic flowers are occasionally 

 produced. 



The zygomorphic character of the flowers of this sub-family shows 

 considerable variation. In Linaria the single anterior petal is spurred. In 

 Diascia there is a spur on each of the anterior lateral petals. In Calceolaria 

 the spur is short but is formed as in Linaria, from the anterior petals. In 

 Antirrhinum the two carpels are unequal in size, the anterior being con- 

 siderably the larger. Peloric anomalies occur in Linaria, the flowers be- 

 coming actinomorphic by the formation of spurs on all the petals. 



The genus Scrophularia is common in north temperate regions. There 



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