PROLIFERATION OF SPIKELETS IN BRITISH GRASSES 



43 



1931). Germination of an undetached seed is included by Arber in ' true vivipary,' and 

 she quotes Spartina townsendii H. & J. Groves as a British example. Germinating seeds 

 may be distinguished from proliferated spikelets by the coleoptiles of the seedlings, see 

 Figure 2. 



The use of derivatives of * prolifer ' as recommended by Arber, has the support 

 of antiquity. Tournefort (1700) used 'proliferum' in a synonym of Poa hulbosa var. 

 vivipara. The viviparous forms of P. alpina L., P. bulbosa L. and Festuca vivipara (L.) Sm. 

 are discussed by Scheuchzer (1719) under the general heading "... Locustis foUaceis 

 proh/eWs proliferated leafy spikelets. However, 'proliferation' unless prefaced by 

 * vegetative ' is not free from ambiguity. Among Arber's references to this phenomenon, 

 a hybrid wheat of Biffen & Engledow (1926) is quoted. This wheat bore numerous 

 florets on an elongated axis, but was innocent of vegetative development. Proliferation 

 has been used to- describe various pathological forms (e.g. in Agrostis canina L., Philipson, 

 1935) which do not bear leafy shoots. 



Other sources of confusion are provided by vegetative shoots terminated by a group 

 of many axillary buds separated by very short internodes. Especially when the buds 

 grow out, the whole presents an appearance superficially resembling a proliferated culm, 

 see Figure 3. The ' mop ' habit of Arber falls into this category. The absence of glumes 

 distinguishes these from proliferated culms, but the margin between extremely meta- 

 morphosed inflorescences and vegetative shoots is not sharp. 



I'ig. J. Puccinellm niaritinia (Muds.) Pari. ]3lakcncy, June 195U. A Uift ol' many shootb upon an clony.atcd 



stolon, similar to 'mop' (Aibcr) (x c. 5). 



In this paper it seems natural to follow the general usage in the literature. ' Viviparus ' 

 derivatives will be used in ecological discussions, because they are strongly entrenched in 

 the taxonomic literature and they emphasize the fact of growth at the time of dispersal. 

 But, whenever morphological and physiological aspects are under review, the mure 

 accurate * prolifer ' words must be used. 



3. The British races of viviparous grasses 



The following are included in the British flora, but Poa bulbosa L. var. vivipara Kocl. 

 is almost certainly not native and the present author has never seen it growing wild. 



