I9I2 



A TEXTBOOK OF THEORETICAL BOTANY 



Pinguicula is restricted to northern temperate parts of the world. Their 

 carnivorous habits will be described in detail in Volume IV. 



The other three genera are Genlisea, a tropical American and African 

 genus, Pohpompholyx in tropical Australia, and Biovidaria which occurs in 

 the West Indies. All are insectivorous. 



The Gesneriaceae are a much larger family, with over 1,100 species 

 and 100 genera. They are mainly tropical and subtropical herbs and shrubs. 

 Several are cultivated in gardens, e.g., Strep- 

 tocarpus (Fig. 1834), Ramondia and Sinningia 

 speciosa which, under the name of Gloxinia, 

 is often grown as a stove plant on account of 

 its large trumpet-shaped flowers of red or 

 purple. Many forms with bicoloured flowers 

 have been produced in cultivation. (Germin- 

 ation of Streptocarpus, see p. 1596.) 



Fig. 1834. — Streptocarpus sp. Flowers. 



Fig. 1835. — Cohimnea schie- 

 deana. Flower, scarlet 

 and vellow. 



Species of the genus Cohimnea (Fig. 1835) are occasionally seen in this 

 country as greenhouse climbers with succulent leaves. There are about 

 seventy-five species in tropical America, several of which live as epiphytes. 

 Anisophylly frequently occurs, large and small leaves forming opposite 

 pairs. 



The Orobanchaceae are by some considered to be parasitic degenerate 

 forms of the Gesneriaceae. The latter family is also closely allied to the 

 Bignoniaceae and the Scrophulariaceae. 



The Bignoniaceae are a somewhat smaller family than the last with 

 some 600 species arranged in over 100 genera. The plants are mostly trees 

 or shrubs or woody climbers forming large lianas. These latter comprise a 

 large proportion of the climbers of the tropical American forest. Many, 

 especially those in Brazil, are pollinated by humming-birds. The anatomy 

 of these stems is anomalous, the xylem being more or less divided into wedge- 

 shaped masses separated by parenchyma. The fruits are capsules and the 



