72 



BOTANY FOR BEGINNERS. 



[Ch. 



Fig. 50. 



288. liliaceous, a corolla with six petals, spreading gradually 

 from the base, so as to exhibit a bell-form appearance,^ in the 



rr i 1 i T 1 ' 



I ulip and Lily. 



289. Rosaceous, a corolla formed of roundish spreading petals. 

 without claws, or with very short ones, as the Rose, and Apple. 



290. Papilionaceous, a flower 

 with a banner, two wings, and a 

 keel ; the name is derivec 1 from the 

 word papilio, a butterfly, on ac- 

 count of a supposed resemblance 

 to this insect, as in the Pea blos- 

 som, (Fig. 50.) 



291. When a corolla is of no 

 determinate form, it is said to be 

 anomalous. 



Odour of Flowers. 



292. The odour of flowers has its origin in the volatile oils, 

 elaborated by the corolla. 



293. Temperature renders the odours of flowers more or less 

 sensible; if the heat is powerful, it dissipates the volatile oils 

 more rapidly than they are renewed ; if the heat is very feeble, 

 the volatile oils remain concentrated in the little cells where 

 they were elaborated ; in both cases the flowers appear to have 

 but little odour. But if the heat is neither too great nor too little 

 the volatile oils exhale without being dissipated, forming a per 

 fumed atmosphere around the flowers. 



294. You see now the reason, that when you walk in a gar- 

 den in the morning, or towards evening, the flowers see'm more 

 fragrant than in the middle of the day. The air being also more 

 damp causes an increase of fragrance at those times, as the 

 moisture, by penetrating the delicate tissue of the corollas, ex- 

 pels the volatile oils. 



288. What is a liliaceous corolla 7 



289. What is a rosaceous corolla! 



290. What is a papilionaceous corolla ? 



291. When is a corolla said to be anomalous? 



292. What causes the odour of flowers? 



293. What effect has temperature upon the odour of flowers? 



294. Why do flowers appear peculiarly fragrant in the morning 

 aid evenirg 1 



