Primula Davidii and its Allies. 
BY 
WILLIAM GRANT CRAIB, M.A., 
Lecturer on Forest Botany and Indian Forest Trees 
in the University of Edinburgh. 
AT the time of Pax’s elaboration of the genus Primula in 
Engler’s Pflanzenreich only two species of this group were 
known, viz. P. Davidii and P. ovalifolia, both described by 
Franchet from David’s Moupin plants. These species were 
placed by Pax in his section Bullatae, although Franchet had 
already correctly indicated their affinity to P. petiolaris. The 
consequent lack of uniformity in the section as understood by 
Pax has already been commented on by Professor Balfour * in 
his account of the Primulas of the Bullatae section. Both from 
habit and from fruit characters P. Davidii and its allies must 
be placed as a rather well-defined group of the Petiolaris section. 
The members of the Petiolaris section would then have in 
common the “ characteristic enlargement of the scape and 
pedicels in fruit- ripening, and for the fruit itself a discoid 
operculate capsule occupied by a broad convex placenta upon 
which the seeds lie.” + 
_ The members of the Peftiolaris section fall into several more 
or less well-defined groups: (1) the fetzolaris group, as typified 
by P. petiolaris, P. sessilis, etc.; (2) the sonchifolia group, as 
typified by P. sonchifolia, P. Whitei, etc.; (3) the Davidi 
group, as typified by P. Davidii, P. ovalifolia, etc.; and (4) 
the Griffithii group, as typified by P. Griffithii, P. Roylei, etc. 
_ Of the first two groups an account has already appeared in 
this publication.t- Specimens of the Grifithi: group have not 
yet been fully examined. In P. hylophila we have a transi- 
tional form between the Davidii group and such species as P. 
ddontocalyx and P. moupinensis of the petiolaris-sonchifolia 
group. In the present group we find the thick, erect, closely 
Pinibiced rosette scales of P. sonchifolia replaced by brown 
lax, paleaceous scales. Except in P. Esquiroliu a well-developed 
* Balf. f. in Trans. Bot. Soc. Edin., xxvi, p. 188 (1913). 
+ Balf. f. in Notes Roy. Bot. Gard. Edin., ix, p. 174 (1916). 
+ Craib in Notes Roy. Bot. Gard. Edin., vi, p. 257 (1917). 
{Notes, R.B,G., Edin., No. LIV, October 1919.] 
