TRAGOPOGON PRATENSIS IN THE CENTRAL COTSWOLDS 



By D. M. Barling ' 

 Royal Agricultural College, Cirencester 



Three subspecies of Tragopogon pratensis L. are listed by Clapham (1952) but in 

 the Flora of Gloucestershire (Riddelsdell, Hedley & Price, 1948) two of these subspecies 

 are recorded as distinct species, namely, T. minor Mill, and T. pratensis L., and it is stated 

 that the records do not distinguish clearly between them, it being thought that the great 

 majority of the plants belong to T. minor. Thus a study of the distribution and cytology 

 of T. pratensis and its subspecies was made in the Cirencester area, embracing much of 

 the central Cotswolds and coinciding with botanical districts 6 and 7b of Gloucestershire 

 which are parts of vice-counties 33 and 34. 



In the Central Cotswolds T. pratensis is exceptionally common on road verges, a 

 fact which greatly facilitated the sampling, and is also found in waste places such as old 

 quarries and gravel pits. The species is common on permanent grasslands, being most 

 abundant on rough pastures subjected to little interference by man. The soils 

 colonised in the area were chiefly over the Oolitic limestones with a pn of approximately 

 7-2, though other soils were the Fullers earth, pn 6-2, Alluvial soils, pH 7-0, and Corn- 

 brash, pH 7-0, determined by pH meter. The main characteristics of the subspecies were 

 studied by the individual examination of 2,450 plants from a wide variety of habitats and 

 all have been found to be T. pratensis subsp. minor. The observations were made when 

 capitula were open, for reasons discussed below. Further and more detailed data within 

 a single population at Deer Park, Cirencester, were obtained from a limited number 

 of specimens. 



Table 1 



Plant characters of T. pratensis subsp. minor from Deer Park, Cirencester 



Character 



Sample size 



Mean 



1. 



Number of basal branches 



45 



5-6 ± 0-62 



2. 



Number of capitula per plant 



100 



17-2 ±0-91 



3. 



Number of florets per capitulum 



100 



55-35 ± 1-07 



4. 



Number of ligules per capitulum 



100 



8-39 ± 0-11 



5. 



Number of achenes per capitulum 



50 



34-94 ± 2-02 



6. 



Number of fruiting heads per plant 



50 



16-86 ± 1-31 



As the identification of the subspecies depends chiefly upon floral characters, the 

 structure and behaviour of the capitula were closely investigated. The apical capitula 

 open first and do so during the morning between 7.0 a.m. and 2.10 p.m. B.S.T. at Ciren- 

 cester. The outer florets of the capitulum open first and are about or just over half the 

 length of the bracts. The corolla is bright yellow, and the anthers are purple 

 to brown above and yellow below. A pale yellow, bifid stigma leads to an inferior ovary, 

 there being a pappus of hairs. Observations showed that the closed stigma emerges 

 through the fused anthers which split along their inner walls thus dusting the outer 



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