III. — BOTANY 



Art. XXXIX. — On the Pollination of Rhabdothamrms solan - 



dri, A. Gunn. 



By D. Petrie, M.A. 



[Read before the Auckland Institute, 7th July, 1902.] 

 Rhabdothamnus, a genus of the GesneriacecB, is the only New 

 Zealand representative of this extensive order of tropical and 

 subtropical plants, and B. solandri, A. Cunn., is its only 

 species. The Maori name is " kaikaiatua." 



The plant is known to range throughout the North Island, 

 and is fairly plentiful on the edges of the more open forests of 

 this district. It is a slender much-branched shrub, of com- 

 pact habit, and 6 ft. to 8 ft. in height. In the vicinity of 

 Warkworth and of Whangarei it is plentiful, in both of which 

 districts I had opportunities of studying it last November. 



The flowers grow singly or in pairs in the axils of the 

 leaves, and are produced in considerable numbers, appearing 

 in a constant succession throughout the summer. They are 

 bome on short slender pedunclts, and stand out from the 

 twigs sometimes in a horizontal but usually in a slightly 

 drooping position. The corolla, which is pale-orange with 

 red stripes, and from -|in. to fin. in length, is distinctly con- 

 spicuous. It is irregular in form, being two-lipped, the upper 

 lip shortly two-lobed and the lower more deeply three-lobed. 

 The external surface is more or less pubescent-pilose, but the 

 inside of the cup is perfectly smooth 



The stamens, four in number, are inserted near the bottom 

 of the corolla-tube. A fifth imperfect filament is sometimes 

 present. 



The two upper filaments are nearly straight, and lie 

 directly along the upper part of the corolla-tube, while the 

 two lower sweep downwards and outwards in a bow-like curve 

 along the lower interior surface of the tube, bending sharply 

 at their ends so as to nearly meet the apices of the upper 

 pair. 



The anthers cohere, even in the unopened flower, into a 

 cruciform or somewhat horse-shoe-shaped disc. When the 

 flower opens the anther disc lies at the mouth of the 

 corolla, almost touching the upper border of its tube, and is 

 so placed that the front of the pollen-sacs faces the axis of 

 the flower. The back of the disc, formed from the confluent 

 connectives, is smooth and polished. As soon as the flower 

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