Arctic Plants: Morphology and Synonymy 37 b 



a flowering specimen froin the south coast of Coronation gulf measures in height 

 no less than 18 cm., and a fruiting specimen from Herschel island 10 cm., the 

 • mature pods averaging about 8 . 5 cm. in length. The specimens from Bernard 

 harbour, on the other hand, are very low, representing compact cushions of 

 leaves from 2 to 6 cm. in diameter; in such specimens the flowers are barely 

 raised above the leaves. 



As stated above, the plant is perennial which is readily to be seen from 

 the subterranean stem-portion bearing numerous remnants of leaves from 

 previous years and emitting short lateral branches with rosettes and flowers; 

 moreover, in several old specimens small leafy rosettes were developed, but still 

 too young to produce flowers. The large fruiting specimens from Herschel 

 island have many green leaves in clusters, indicating that future growth is 

 secured. The primary root persists throughout the life of the plant and in- 

 creases quite considerably in thickness and length, ramifying freely, the lateral 

 branches equalling the primary in length. 



Cardamine pratensis L. 



This seems to thrive well on the arctic shore; the specimens are tall and 

 blooming freely; a specimen from Port Epworth harbour measures 24 cm. in 

 height and bears three lateral racemes developed from the axils of the cauline 

 leaves. It is a point of interest to notice that in some of these high northern 

 specimens (Coronation gulf) vegetative reproduction is secured by means of 

 adventitious buds developed upon the basal leaves close to the leaf-segments. 

 These buds upon the leaves of Cardamine were^ described already by Cassini; 

 while still in connection with the leaf they develop some small leaves and roots 

 and, when liberated, they continue their growth and develop new independent 

 individuals. Similar buds are known also from a few other plants. Turpin 

 observed them in Ornithogalum, Henslow in Malaxis, and according to Lindley ' 

 they abound in Bryophyllum and Tellima grandifiora. 



With regard to the fruit in Cardamine, the specimens showed mostly flowers 

 and only a few young pods were developed. Thus in case of failure to produce 

 seeds, Cardamine would be able to become distributed by means of the adventi- 

 tious buds. 



C. digitata Richards. 



In a monograph of the genus Cardamine 0. E. Schultz ^ rejects Richardson's 

 name "digitata" because the genus has become merged into the genus Dentaria 

 of which there is a species "digitata" of older date, thus necessitating the creation 

 of a new name for Richardson's plant. 



"Dentaria digitata Lamarck" must consequently be renamed Cardamine 

 digitata (Lam.) Schultz, and "C. digitata Richards." must bear the name Carda- 

 mine hyperborea Schultz. However, it all depends on the concept of the two 

 genera Cardamine and Dentaria, whether they should be kept separate or be 

 united. This question has been raised before by some of the ablest botanists 

 abroad and on this continent and the question seems to be well solved by Gray, 

 Greene, Nuttall, Sereno Watson, and several others who were' familiar with the 

 species of both genera as represented on this continent, maintaining the genus 

 Dentaria as distinct from Cardamine. 



With respect to the subterranean stem, C. digitata possesses a slender, 

 horizontally creeping rhizome which bears aerial, green leaves and which is 

 also stoloniferous. In this way the species is better equipped to become dis- 

 tributed than C. pratensis in case of failure to produce mature seeds in unfavour- 

 able seasons. By the constantly smaller size of the flowers, the shape of the 

 leaves, and especially by the rhizome, C. digitata is a good species, and well 

 distinguished from C. pratensis. 



' Introduction to Botany. London, 1832, p. 50. 



' Engler's bot. Jahrb. Vol. 32. Leipzig, 1903, p. 550. 



