T. Holm — North American Species of Stellaria. 319 



the life of the polar-plants.* In this species the rhizome con- 

 sists of long stolons with small scale-like leaves, and stretched 

 internodes. The aerial shoots are ascending, and the leaves 

 are more or less crowded on account of the shortness of the 

 internodes. When the winter commences the leaves are still 

 attached to the shoots, but in a withered condition ; the stems, 

 on the other hand, remain alive and persist throughout the 

 winter. At the beginning of the spring small buds become 

 visible in the axils of the withered leaves, which soon develop 

 into small leafy shoots. These shoots frequently remain vege- 

 tative for one or two years until they become terminated by 

 an inflorescence. We have, thus, in this species of Stellaria a 

 very interesting example of herbaceous aerial stems, which 

 winter over, and produce axillary buds, the function of which 

 is to develop assimilating leaves, new axillary buds, and finally 

 to produce flowers and fruits. This method of reproduction 

 we observed, also, in the alpine plant, but in this the axillary 

 shoots frequently reach the flowering stage already in the first 

 year of their growth. 



Several other species of Stellaria exhibit this type of vege- 

 tative reproduction, for instance : S. longifolia Muehl, S. 

 humifusa Kottb., S. Holostea L.,f and S. crassifolia Ehrh. 

 But in S. horealis Big. (specimens from Hudson Bay, and St. 

 Paul island in Behring Sea), and in S. crispa Cham, et Schl. 

 (from Annette island, Alaska) we observed only the subterra- 

 nean stolons ; thus it appears as if the aerial stems of these two 

 species do not persist throughout the winter. 



As representing this type may, furthermore, be mentioned 



Stellaria umbellata Turcz. 



This species we collected in Colorado on the summit of the 

 mountains (above 14,000 ft.), where it grows among bowlders, 

 associated with Claytonia megarhisa, Trifolium manum, 

 Saxifraga cernua, S. flagellar is, S. nivalis, Poa Lettermannii, 

 etc. ; it occurs, also, at lower elevations, for instance in the 

 Spruce-zone on Mt. Massive (10,500 ft.). — In the alpine plant 

 the aerial shoots (fig. 2) are very short with crowded leaves and 

 a small, terminal inflorescence, mostly three-flowered ; the stems 

 persist throughout the winter, and minute buds become formed 

 in the axils of the withered leaves as in S. longipes. There is 

 a very distinct rhizome, consisting of several stolons, in which 

 the internodes are very short, and mostly shorter than the 



* Ur Polarvaxternas liv (in A. E. Nordenskiold's Sttidier ach Forskningar, 

 Stockholm, p. 513, 1884). 



f An interesting account of the hibernation of this species has been 

 given by O. G. Petersen (Bot. Tidsskr., ser. 2, vol. 4, Kjoebenhavn, 1874- 

 76, p, 30), who has, also, described the development of cork as it occurs in 

 Caryophyllacece, and the structure of the pericycle (ibidem, p. 187, 1888). 



