Edith R. Saunders 223 



pointing to a hybrid origin. For we find within the genus, besides the 

 group of tj'pes closely allied to purpurea and like jjutesce**.* having the stem 

 pubescent or tomentose throughout, as e.g. Thapsi L., tomentosa Link and 

 Hoffmgg., MariaiM Boiss., nevadensis Kze. and duhia Rodr.', and those on 

 the other hand which like laevigata W. and K., laciniata Lindl., obscura L. 

 and ferruginea L. are smooth-stemmed throughout, a considerable 

 number of forms which exhibit us a recognised normal feature a similar 

 transition from a glabrous condition in the vegetative to a hairy condition 

 in the flowering region of the stem. Well-marked examples of this class 

 are D. lanata Ehrh., a Hungarian species, and the Portuguese form 

 D. miniana discovered by Sampaio and described by him in 1905, in both 

 of which the transition in surface character is definitely recognised as a 

 diagnostic character. Among cases less pronounced or possibly only less 

 clearly recognised we may probably include ambigua Murr., sibirica Lindl., 

 leucophaea Sibth., paruijioru Jacq.- and perhaps orientalis Lam. and 

 Intea L.^; also piirpurascens Roth, considered by some as a hybrid form 

 and fuscencens W. and K., the last-mentioned a rare Hungarian plant 



' All these types appear to be closely related to purpurea. Beautiful illustrations of 

 tomentosa and Thapsi are given in Flore Porlugaise by Link and Hoffmansegg, where 

 tomentosa and purpurea are compared in detail. According to Brotero (PhijtoyrapJiie, T. ii. 

 1827, tab. 149, p. 1-59) tomentosa is not to be regarded as distinct from purpurea but merely 

 as a southern race of that species to which it is linked by intermediate forms. Tliapsi is 

 described by Liudley (loe. cit.) as also very similar to purpurea, and by Koelreuter (Acta 

 .lead. PetropoL, 1777) is regarded in the same light as tomentosa. G. W. F. Meyer takes 

 the same view (Chloris Hanoverana, 1836, p. 323). Mariana is another form, according 

 to Boissier (Voy. Bot. T. n) closely akin to purpurea, while duhia is considered by 

 Rodriguez (Plantas vasculares de Menorca, 1874) to be intermediate between Thapsi and 

 minor, the flowers of the latter species being described by Linnaeus as again very similar 

 to those oi purpurea. 



- From systematic descriptions of these species where little importance attaches to t)ie 

 nature of the stem surface as a diagnostic character it is less easy to gather the precise 

 degree of difference between the upper and lower region. Though no specific statement 

 may be met with in the text reference to the illustration, where such is given, will some- 

 times clearly show that the plant exhibited this transition character, as is seen, for example, 

 in the case of Z). oehroleuca described and figured by Jacquin in Fl. Aust. i. p. 36, pi. 58, 

 1773. 



'■' Though lutea is generally spoken of as glabrous Lindley describes the stem as very 

 glabrous or pubescent, and Henslow also draws attention to the possibility that absence of 

 hairs in this species is not a fixed character. Hpeciraeus from near Siena in the Bunbury 

 Collection (Cambridge) show numerous hairs on the margins and on the veins of the under 

 surface of the leaves, and on bracts and sepals, but the stem appears to be hairless. Whether 

 the appearance of hairs on the stem in this case is a fluctuating character and varies with 

 conditions or whether there are two distinct and constant forms I have not sufficient data 

 to determine. It is possible that the same question may arise in regard to orientalis and 

 perhaps also with laevigata as well. 



15—3 



