Arctic Plants: Morphology and Synonymy 



11 B 



To consider the species as a mere variety of G. maritima, as has been done 

 in recent years, is open to question, and Johanson ^ has written a very instructive 

 paper, demonstrating that G. vilfoidea and G. maritima are not conspecific. 



Lange gives a good diagnosis of G. vilfoidea (Conspectuslc. p. 170) as follows: 



"Gracilis, glaberrima, rhizomate obliquo, foliorum fasciculos-abbreviatos 

 et flagella yalde elongata gracilia emittente; foliis anguste linearibus subcompli- 

 catis, acutis; ligula brevi, truncata; panicula brevi, contracta, ramis sub anthesi 

 adpressis, defloratis erecto-patentibus, inferioribus subgeminis, super, solitariis; 

 glumis obtusis inp,equalibus flosculis 2-3, palea inf. ovali, obtusa, 3-5-nervia." 



''Obs. Species haec, non nisi e Groenlandia et ins. Spidsberg. hucusque 

 cognita, rnodo crescendi aliisque characteribus a G. maritima recedit, etsi hujus 

 tormis quibusdam {G. maritima var. arenaria E. Fries Mant. 2. p. 9) affinis est." 



Rguee B. 

 1. Stolon of Glyceria vilfoidea (Ands.) Th. Fr.;P=the prophyllon (fore-leaf); L= lateral shoot; 

 S=priinary shoot; natural size. (St. Paul island, Bering strait.) 2. Stolon of Catahrosa 

 aguaiica (L.) Beauv.; St = flower-bearing stem; other letters as above; natural size. (Sweden). 

 3. Two viviparous spikelets of Aira alpina L.; magnification If (Greenland). 



For a comparison I have drawn the spikelets of both (Fig. A: 4-5 and 6-7). 



Moreover, as pointed out by Johanson (I.e.), the structure of the stolons 

 differs in a marked degree from that of the other species of Glyceria, and seems 

 indeed to be rare, or at least but little known from Gramineae in general. The 

 accompanying text figure (B) shows part of a stolon of G. vilfoidea (fig. 1) ; in this 

 the main shoot is aerial (S), and bears several green leaves, separated from each 

 other by stretched internodes; at each node a small lateral shoot is developed 

 (L), of which the first leaf represents an adorsed prophyllon (P) or fore-leaf, as 

 is the usual structure of lateral shoots in the monocotyledons. But, as may 

 be seen from the drawing, the lateral shoot is not situated in the axil of the 

 corresponding stem-leaf, but has been moved up to the node above, thus occupy- 

 ing a very strange position, remote from the leaf-axil. It is a structure that 

 recurs in the genus Catahrosa, for instance, inC. aquatica (L.) Beauv., where the 

 structure is very plainly visible (fig. 2); in this plant the stolons appear to root 

 more freely, the secondary roots proceeding from the nodi, as shown in the 

 drawing. 



The fact that G. vilfoidea seldom produces flowers, and that fruiting speci- 

 mens are almost unknown, indicates that vegetative reproduction supersedes 

 the floral, and in this respect G. vilfoidea is readily distinguished from the other 

 ?pecies of the genus. While vegetative reproduction is known to be prevalent 



1 Om Glyceria maritima (Huds.) Wahlenb. var. arenaria och Glyceria vilfoidea (Ands.) Th. Fr. (Sv. 

 Bot. Tidskr. 4. Stockholm, 1910). 



