ACANTHACEAE 



239 



686. Ruellia Plum. 



2203. R. tuberosa L. (= Cryphiacanthus barbadensis Nees). Dillenius pointed 

 out that this species bears cleistogamous flowers (von Mohl, Bot. Ztg., Leipzig, xxi, 

 1863, p. 310). 



687. Aechmanthera Nees; 688. Doedalacanthus Anders; 

 689. Eranthemum L. 



Species of these genera sometimes bear cleistogamous flowers. 



690. Aphelandra R. Br. 



2204. A. cristata R. Br. (Delpino, 'Ult. oss.,' pp. 231-2.) In the flowers 

 of this species two of the four corolla-lobes surround the anthers, the remaining two 

 forming a door closing the entrance. When this is opened the upper corolla-lobes 

 separate, so that the anthers are freed, and scatter pollen on visitors. 



Visitors. Delpino supposes that these are humming-birds. 



691. Rhinacanthus Nees. 



2205. R. communis Nees. (Delpino, 'Altri appar. dicog. recent, oss.') In 

 the markedly protandrous flowers of this species the anthers of both stamens, which 

 bend down into the mouth of the flower, dehisce during the first stage of anthesis, 

 while the still immature stigma is bent upwards. In the second stage the stigma is 

 mature and stands in the way of the visitor's proboscis, while the stamens are bent 

 towards the sides. 



Visitors. Delpino supposes that these are Lepidoptera. 



692. Thunbergia Retz. 



2206. T. alata Boj. (Hildebrand, Bot. Ztg., Leipzig, xxv, 1867, p. 285.) 

 When an insect pushes its way into the flowers of this species, it brushes with its 

 back first the stigma and then the anther-processes, so that it is covered with pollen, 

 which it transfers to the stigma of another flower. 



2207. T. erecta T. Anders (= Meyenia erecta Benih.). This species is 

 indigenous to West Africa. Its flowers grow almost horizontally. The bilobed 

 stigma is situated in the mouth of the flower ; only its upper part is receptive, and it 

 is rolled up into a tube. On being visited by an insect, the lower part of the stigma, 

 which stands directly in its way, is pressed so far down that the receptive upper 

 portion reaches the insect's back, and, if this is already covered with pollen, takes up 

 some of it. If the insect pushes further into the flower, it is dusted anew, for the 



anthers are situated in the middle of the corolla-tube and are provided with hairs, 

 which catch the falling pollen. When the visitor creeps out of the flower, the lower 

 part of the stigma prevents the upper from being self-pollinated. 



693. Strobilanthus Blume. 



2208. S. anisophyllus T. Anders (= Goldfussia anisophylla Nees). (Morren, 

 Nouv. M^m. Acad, roy., Bruxelles, vi, 183 1, xii, 1839.) In this species also the 

 flowers are almost horizontal. Only the lower side of the stigma is receptive, and 



