HELIANTHEMUM CAROLINIANUM. CAROLINA SUN ROCK-ROSE. 79 



taken. To save confusion we have ventured to add a prefix, and 

 so have made "Sun Rock-roses." 



There are many interesting facts probably remaining to be 

 discovered in connection with our plant and its American com- 

 rades. The original species of Europe, which gave its name to 

 the genus, has sensitive stamens, falling back on the petals if 

 touched when the flower is expanded during sunshine. Darwin, 

 the grandfather of the present illustrious philosopher who wrote 

 near a hundred years ago, seems to have been aware of this 

 fact. In his poem, " The Loves of the Plants," he says : 



" Fair Cista, rival of the rosy dawn, 

 Called her light choir, and trod the dewy lawn ; 

 Hailed with rude melody the new-born May, 

 As cradled yet in April's lap she lay." 



And in a note he says: "The flowers continue expanded but a 

 few hours, falling off about noon or soon after, in hot weather. 

 The courtship between the males and females in these flowers 

 might be easily watched ; the males are said to approach and to 

 recede from the females alternately." In this fanciful strain he 

 refers to what we now understand by pollenization. 



Again in some of the allies of our species it has been noted, 

 according to Don, and as specially referred to in the lines from 

 Darwin, that they derived the name Helianthemitm "because 

 they open with the rising of the sun in the morning, and the 

 petals fall off with the setting of the sun in the evening. But 

 they only continue open as long as the sun shines. If the 

 weather is dull, and the sun does not make its appearance, the 

 flowers do not open, but remain unexpanded. Should this con- 

 tinue for several days together, they will decay in the bud." But 

 in American species it has been noted that there are often some 

 flowers which never open or show petals, sun or no sun — and 

 just how the others open under sunshine has not been accu- 

 rately noted. It is believed that the one we now describe, the 

 Carolina Sun Rock-rose, always has complete flowers. At least 

 Chapman, the most recent author, says so ; but Torrey and Gray, 



