36 



ANGIOSPERMAEDICOTYLEDONES 



Fig. 222. Cassiope tetragona^ D. Don (after E. Warming). 

 A . Diagram of a flower seen from the side ( X 4). B. A stamen. 

 C. Diagrammatic plan of the same. D. Longitudinal section of 



a flower (x 4). E. Stamens and stigma seen from below (x 10). 



522. Cassiope D. Don. 

 Bell-shaped pendulous flowers, with nectar secreted by yellow nectaries at the 

 base of the ovary. 



1760. C. tetragona D. Don. (Warming, Bot. Tids., Kjobenhavn, xv, 1885, 

 pp. 25-9.) Warming thinks this arctic species possibly belongs to flower class Lm. 

 The yellowish-white flowers exhale an odour of hawthorn, especially towards evening. 



The pollen is scattered by 

 the impact of the proboscis 

 of insect visitors against the 

 diverging appendages of 

 the anthers. Crossing by 

 insects is possible, but in 

 Greenland automatic self- 

 pollination generally takes 

 place while the flowers are 

 closed. 



The species is abundant 

 on heaths in Spitzbergen, 

 and Ekstam says that 

 its pendulous flowers erect themselves when anthesis is over (' Blutenbiol. Beob. 

 a. Spitzbergen,' p. 9). It blossoms in that island from the end of June to the 

 middle of September, and sets abundant fruits (Andersson and Hesselman, ' Bidrag 

 till Kanned. om Spetsbergens o. Beeren Eil. Karlvaxtflora,' p. 18). Vanhoffen was 

 unable to perceive the odour of hawthorn described by Warming (Abromeit, ' Bot. 

 Ergeb. von Drygalski's Gronlandsexped.,' p. 49). 



Visitors. ^Ekstam observed numerous small insects in Spitzbergen. 



1761. C. hypnoides D, Don (= Andromeda hypnoides Z.). (Warming, op. cit.. 

 pp. 29-31.) Warming describes the flowers of this species as white with purple-red 



corolla-lobes. They are more 

 widely open than those of the 

 last species, and Lindman says 

 that they possess a tolerably 

 strong odour. Warming found 

 the species to be homogamous 

 in Greenland, but on the Dovre- 

 fjeld Lindman observed that 

 the flowers were at first pro- 

 togynous, afterwards becoming 

 homogamous. Autogamy result- 

 ing in the setting of numerous 

 fruits apparently takes place 



before the flowers open, by fall of pollen upon the clearly defined stigma, which 



is covered with a sticky resinous fluid. {C/. Fig. 223.) 



Yanhoff"en compares the species to a Polytrichum in habit, and he found it 



in Greenland with numerous (.-* last year's) fruits, collected together under the delicate 



Fig. 223. Cassiope hypnoides, D. Don (after E. Warming). 

 A, Flower in longitudinal section, seen from the side ( X 4). B. Do., 

 seen from below (x 4). C. Style (x 5). D. A stamen, seen from 

 the side. E. An anther. F. A stamen, seen from the inner side. 



