HYBRIDISATION OF EUPHRASIA 



257 



since it is far from typical of that species, and to some extent resembles E. micrantha, 

 the name will be used in quotation marks. It might conceivably be a hybrid between 

 E, micrantha and E. confusa or E. nemorosa (Pers.) Mart., but it appeared quite uniform. 

 E. confusa is not considered important and will not be mentioned further; the other 

 three forms occurred in large quantity. Their characters are shown in Table 2, and 

 photographs of E. "nemorosa" and E. vigursii are given in plate 17, fig. 2, numbers 1 and 2. 



Of the characters listed in Table 2, E. vigursii resembles E. anglica exactly in only 

 one (chromosome number), E. " nemorosa " in two, and is intermediate in three, being 

 nearer E. anglica in two of these. In addition, it is outside the range of these two species 

 in the four floral characters listed. It will be noted that the characters in which E. vigursii 

 resembles E. " nemorosa " are those of habit. 



Table 2. 



Characters of the Euphrasias at Roborough Down 



Name 

 Collector's Number 



E. anglica 

 E19S 



£. vigursii 

 E197A 



E. " nemorosa " 

 £196 



Internodes 



Short 



Long 



Long 



Position and length of 

 branches 



Basal, not much ex- 

 ceeded by main stem 



Central, much exceeded 

 by main stem 



Central, much exceeded 

 by main stem 



Leaf shape 



Broad 



Intermediate, rather broad 



Narrow 



Anthocyanin in leaves 



Probably a trace 



Less than in "nemorosa" 



Usually present 



Foliar glands 



Dense, long 



Dense, long, often less 

 dense than in E. anglica 



Occasional short stalked 

 glands present 



Corolla length 



6-7-5 mm.* 



7-8-5 mm. 



5-5-6-5 mm.* 



Corolla-lip breadth 



5-5-5 mm.* 



6-5-8 mm. 



4-4-5 mm.* 



Shape of lobes of lip 



Nearly parallel-sided 



Considerably dilated 



Narrow, little dilated apic- 



ally 



Corolla colour 



White, with upper lip 

 lilac, or finally faint lilac 

 throughout 



Purplish red to pale lilac, 

 sometimes white with 

 upper lip lilac 



Upper lip lilac, lower 

 usually lilac, sometimes 

 white 



Capsules 



Normal 



Occasionally with reduced 

 numbers of seeds, down 

 to one 



Normal 



Normal looking pollen 



93 per cent. 



c. 64 per cent, but results 

 inconsistent 



100 per cent. 



Chromosome Number 

 (2n) 



Not counted, but 22 in 

 this sp. at several other 

 localities 



22 (Plate 18, fig. 1) 



Over 22 (44 in its nearest 

 relatives) 



* These measurements (especially the lip -breadths) may be underestimated through being taken two days after collection 



No clear chromosome count of E. " nemorosa " could be obtained, but it is very likely 

 that the number is 2n = 44 as in true E. nemorosa and E. micrantha. Meiosis in E. vigursii 

 was seen at early anaphase of the first division (Plate 18, fig. 1), and metaphase of the second 

 division, and appeared normal. 



