Arctic Plants: Morphology and Synonymy 25 b 



rhizome and may remain active for several years. There is no leafy rosette as 

 the cushion is formed only by the numerous branched shoots with their inter- 

 nodes very distinct, and with the leaves opposite. 



Halianthus peploides (L.) Fr. 



This is known best under this name; it is Arenaria peploides L., but the 

 genus has also been called Ammodenia Patrinj Honkenya Ehrh., and Adenarium 

 E,af. The vegetative reproduction is effected by means of long subterranean 

 stolons with membranaceous leaves, scale-like and sheathing, which traverse 

 the ground for some time until they seek the surface where they become trans- 

 formed into aerial shoots with green typical leaves and flowers (Fig. F: 1); 

 many of these stolons ramify freely in the ground; thus the individual represents 

 a mass of floral and vegetative shoots. Very peculiar is the development of 

 dwarfed shoots upon the subterranean noiii of the stolons. They have been 

 described by Warming ^ and, as shown in the figures (Figs. 2-4), they are either 

 simple or ramified. The axis is very short and the leaves of minute size and 

 scale-like; they may persist for several years without developing any further, 

 and, judging from the excellent material collected on the expedition, these 

 shoots may die off without increasing any further in length. Or, as shown at 

 the apex of the long stolon in fig. 2, they may become extended into aerial 

 shoots. As mentioned above, these shoots may develop lateral shoots of the 

 same structure; thus clusters of these may be seen at the root. With respect to 

 the root-system, very thin secondary roots are developed here and there beneath 

 the leaves of the stolons but they are not frequent and no roots were observed 

 to proceed from the upper part of the stojons. No primary root was represented 

 in any of the numerous specimens collected. The seedling stage has been 

 described by Joh. Eriksson^; when growing in sand the cotyledons are hypogeic, 

 and evidently by means of contractile toots the young plant becomes pulled 

 down into the ground; besides true cotyledonary buds two pairs of accessory 

 buds are developed above these. 



FiQUEE ¥. Halianthus peploides (L.) Fr. 



Part of a large stolon bearing a lateral, more slender stolon which, on reaching the surfacj 

 bears green leaves and a flower; natural size. 2. Part of a large stolon bearing severa, 

 dwarfed shoots, one of the apical having grown out and developed an aerial shoot; natura 

 size; specimens from sandspit at Martin point, Alaska. 3 and 4. Two of the dwarfed shoots 

 showing ramifications; in fig. 3 the basal leaves have dropped, leaving distinct scars; thus 

 the shortness of the internodes are readily to be observed; enlarged. 



1 Smaa biologiske og morfologiske Bidrag. (Botan. Tidsskr. 3.R. 2. Bd. Kjoebenhavn, 1877-79, p. 96, 



2 Studier 6fver Sandfloran i ostra Sk^ne. (Bih. K. Svenska Vet. Akad. Hdlgr.Vol. 22. Stockholm, 

 1896.) 



