52 



P. R. \WCHERLEY 



Syme had two viviparous plants of ' intermediate ' type from North Wales under 

 A. cespitosa, which in the absence of others are presumably his var. pseudalpina. There 

 are forty-seven Scottish viviparous specimens, all labelled A. alpina, but including in 

 the present author's opinion the var. pseudalpina, intermediate plants and D. alpina 

 Evidently Syme used glume-keel smoothness as a key character. But this course includes 

 in A. alpina, as interpreted by Syme, many plants hard to bring into D. alpina, and 

 in fact all viviparous Deschampsiae in this present study. 



In order to escape from this impasse of conflicting and overlapping definitions and 

 the lack of any other names free from ambiguity, awn-insertion is used here as the criterion 

 and an ' intermediate ' category maintained. 



All the seminiferous plants with basally inserted awns (D. cespitosa) have been 

 found to have markedly scabrid leaves, panicle branches and glumes. 



Since var. pseudalpina is a segregate of D. cespitosa, a gradation of certain characters 

 from seminiferous D. cespitosa through the var. pseudalpina, the ' intermediate,' to the 

 typical D. alpina might be expected. 



Forty-six viviparous Deschampsia specimens have been classified by the condition 

 of their third glume's awns at the time of collection. Other features were not consistently 

 distributed, so this one major criterion was selected. Even so, the spikelets in a panicle 

 are not all the same, and in deciding the category the whole was considered. It is partly 

 for this reason that the ' intermediates ' have not been lumped with D. alpina, and also 

 because the specimens placed by Syme in A. cespitosa are intermediate. 



In Table 4 the numbers of the plants with different characters are given, and in 

 the first column the condition in seminiferous D. cespitosa. 



The leaves and panicle branches are rougher in proportionately more var. pseudalpina 

 than D. alpina plants, but smooth forms occur in both, although the trend is in agreement 

 with the postulated gradation. 



The midribs of lower glumes of all viviparous plants are innocent of roughness in 

 their lower portions, hence this character from Roemer & Schultes, and Syme, does not 

 separate these plants. Hairiness about the floret base is typical of seminiferous D. cespitosa, 

 but only var. pseudalpina plants were naked. 



Living portions of the plants discussed above were also collected ; sixteen bore culms 

 in London the next year. In April the Deschampsiae were making poor growth and 

 were brought into a glass cabinet, where they obtained additional warmth and illumina- 

 tion. This speeded shooting and was responsible probably for the greater degree of 

 floret-bearing in these conditions than in nature. Except the D. alpina plant which 

 became fully flower-bearing, none of the inflorescences were completely free of prolifera- 

 tion. Established bulbils also bore viviparous culms. Here vivipary is a hereditary 

 character modified by environment. The inflorescences obtained in culture are classified 

 by awn type in the lower part of Table 4. It will be seen that there has been a shift 

 towards D. alpina features. 



It is suggested that this tendency towards D. alpina is associated with the bearing 

 of more floral organs in the forced plants. These plants were further studied and it 

 was noted, especially in the ' intermediate ' group, that, where fully-floret-bearing and 

 viviparous spikelets occurred in the same panicle, the floret lemmas were of a D. alpina 

 character, but the proliferated spikelets usually bore third glumes of an ' intermediate ' 

 or pseudalpina type. As flower-bearing increases, so the awn becomes more clearly 

 distinguished, longer, and inserted lower. Thus decreasing proliferation is accompanied 

 by an approach to D. alpina, and if the trend could be continued, to the typical semini- 

 ferous D. cespitosa form. 



Conversely, increasing vivipary causes a transition from the seminiferous D. caespitosa 



