PROLIFERATION OF SPIKELETS IN BRITISH GRASSES 

 I. The Taxonomy of the Viviparous Races 

 By P. R. Wycherley* 



Department of Botany, University College, Londoji'f 



1. Introduction 



The gramineous inflorescence may be resolved into units termed spikelets. Each 

 spikelet consists of an axis bearing bracts or glumes. Except for the sterile glumes (two 

 in most British grasses) which are inserted lowest upon the spikelet axis, the glumes 

 bear florets in their axils. In this paper the terminology approximately follows that 

 of Arber (1934). Glume will be used to denote any bract directly inserted upon the 

 spikelet axis, but a glume subtending a floret is termed a lemma. 



•1 



Fig. 1 



A. Festuca ovina L. 1. Young spikelet ( x 10) ; 2. Basal portion dissected to show floret development ( X 25) ; 

 I-VIII Glumes (I-III cut away); iii. Palea of lowest floret. B. Festuca vivipara Sm. 1. Young spikelet ( X 10); 

 2. Dissected to show vegetative apex of the spikelet axis (x 25); I-VI Glumes (I-IV cut away). 



Arber calls the continued growth of the spikelet axis, and the bearing of leaves 

 distally upon it, ' vegetative proliferation.' The glumes are found in various stages of 

 metamorphosis from their normal structure to foliage leaves. If the normal lemma has 

 the upper portion of its midrib separated dorsally as an awn, then in proliferated spikelets 

 transitions from awn to leaf-blade are found. The morphological significance has been 

 discussed by Philipson (1934). The florets subtended by the glumes of the proliferated 

 spikelets may be almost normal, male- or female-sterile, aborted or completely absent. 

 Figure 1 shows young proliferated and flower-bearing spikelets of Festuca. 



* The substance of this paper formed part of a thesis approved by the University of London for the Ph.D. degree, 

 t Present address : Rubber Research Institute, Kuala Lumpur, Malaya. 



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