li PART III. | THE MECHANISMS OF FLOWERS. 467 
Orv. ACANTHACE LZ. 
Thunbergia alata, Boj.—The insect entering the tube of the 
_ flower to reach the honey at the base first touches the stigma with 
its back, and then the anthers, which are provided inferiorly with 
pointed processes (352). 
. Cryphiacanthus barbadensis, Nees. (Ruellia clandestina, L.).— 
The cleistogamic flowers were known to Dillenius (531). 
EHranthemum, L., Dedalacanthus, Anders., Dipteracanthus, 
_ Nees." Aichmanthera, Nees., and Ruellia, L., also possess cleis- 
| togamic flowers (167). 
; Meyenia erecta, Benth—The mechanism of the flower of this 
_ West African shrub has been described by Mr. Irwin Lynch (444). 
The flowers stand nearly horizontal. The style lies in a groove 
on the dorsal side of the tubular curved corolla. The stigma, 
_ which stands at the mouth of the tube, is two-lipped ; its upper lip, 
which is alone receptive, is rolled into a tube. 
The anthers stand midway in the corolla tube, and are furnished 
with hairs which catch the pollen as it is being shed. The broad 
lower lip of the stigma projects downwards, obstructing the en- 
trance ; it first acts as a lever to bring the upper lip down upon 
_ the back of an insect entering the flower; but afterwards, as the 
Insect emerges with its back dusted with fresh pollen, the lower 
lip of the stigma protects the upper one from contact. 
Strobilanthes ( Goldfussia) anisophylla, Nees.—This flower was 
| carefully described and beautifully figured by Charles Morren in 
| 1839 (541A). Morren saw that insects were needed to effect fertilis- 
' ation, but he thought only of self-fertilisation, and accordingly he 
' misinterpreted the mechanism of the flower. 
The flowers stand nearly horizontal. The tip of the style only 
bears stigmatic papillz on its lower (anterior) surface ; it is curved 
1 upwards so that an insect in entering the flower comes at once in 
: “contact with the stigma. When thestigmais touched (or even if it 
be breathed upon) it at once becomes straightened out and gener- 
i ‘ally curves at the same time to the right, and it becomes closely 
' appressed to the inferior wall of the corolla. The insect passes 
| further into the flower, and becomes dusted with fresh pollen : this 
is carried out of the flower without coming in contact with the 
| stigma. According to Morren the irritability of the style is never 
_ manifested until after dehiscence of the anthers. 
1 Bentham and Hooker place this genus under Ruellia. 
HH 2 
