132 POLrEMONIACEAE 



arrangement an evolutionary interest which is very striking, even if only partially -understood. 

 Judgments, to be sure, differ aa to the evaluation of Hugelia, Navarretia, Leptodactylon, Sipho- 

 nella, Linanthus, Gymnosteris and Langloisia, which have been, hitherto, most commonly re- 

 ferred to Giiia as subgenera or sections. All these are recognized as genera in this treatment 

 and, aside from the status assigned them, are undoubtedly natural groups as here constituted. 

 CoUomia, here recognized as a genus, seems in some respects artificial. In relation to this genus 

 and to other genera of this family, cytologieal evidence is of interest. The following facts as to 

 chromosome numbers are taken from the paper of W. S. Flory in Cytologia (Fujii jub. vol. 171- 

 180). Various species of Collomia have 8 pairs of chromosomes and are thus distinguished cyto- 

 logically from other genera of Polemoniaceae. Although, in its gross morphology, Hugelia is not 

 markedly differentiated from Gilia, Flory finds that Hugelia, so far as known, has 7 pairs of 

 chromosomes as contrasted with 9 pairs for true Gilia. Linanthus and Leptodactylon have 9 pairs 

 of chromosomes as in Gilia but the chromosomes are measurably smaller. The basic chromosome 

 number in Phlox appears to be 7, while the species of Polemonium have 9 pairs of chromosomes. 

 Bibliog. — Benthara, G., [new genera and species of Polemoniaceae] Bot. Eeg. 19, sub. t. 

 1622, — 1833. Gray, A., Re-sision of the N. Am. Polemoniaceae (Proc. Am. Acad. 8:247-282, — 

 1870). Greene, E'. L., Some American Polemoniaceae.— I. (Pitt. 1:120-139,-1887); II. (Pitt. 

 2:251-260,-1892) ; [types of Californian species of Gilia], (Ervthea 3:103-105, — 1895) ; [new 

 spp. of Gilia], (Erj-thea 3:120-121,-1895); Some western Polemoniaceae (Pitt. 3:299-305,— 

 1898). Milliken, J., A review of Gal. Polemoniaceae (Univ. Cab Publ. Bot. 2:1-71, pis. 1-11,— 

 1904). Eastwood, A., Some new species of western Polemoniaceae (Bot. Gaz. 37:437-447, — 1904). 

 Brand, A., Kulturversuche mit verschiedenen Polemoniaceen-Arten (Engler, Botanische Jahr- 

 biicher 36:69-77,-1905); Polemoniaceae (Engler, Pflzr., 4-'<' : 1-203, figs. 1-39,-1907); Neue 

 Beitriige zur Kenntnis der Polemoniaceen (Ann. Conserv. et Jard. Bot. Geneve 15— 16:322— 342,- — • 

 1913). Nelson, A., & Macbride, J. F., Gilia and Collomia (Bot. Gaz. 61:34-35,-1916). Mac- 

 bride, J. F., Gilia virgata and allies (Contrib. Gray Herb. 49:51-58, — 1917). Craig, Thos., A re- 

 vision of the subgenus HugeUa of the genus Gilia (Bull. Torr. Club, 61:385-396, pi. 23,-1934: 

 61:411-428, — 1934). Constance, L., and Rollins, R. C, Gilia congesta and its allies (Am. Jour. 

 Bot. 23:433-440, — 1936). Constance, L., The type locality for Gilia congesta (Lflts. W. Bot. 

 2:21-22, — 1937). Mason, H. L., Two new species of Linanthus from western N. Am. (Madrono 

 4:157-160, pi. 28, — 1938). Flory, W. S., Chromosome numbers in the Polemoniaceae (Cytologia, 

 FujU jub. vol. 171-180,-1937). 



A. Corolla regular. 



Leaves pinnately compound, the leaflets sessile on the rachis, the uppermost sometimes confluent ; 

 corolla tubular-funnelform to nearly rotate; calyx wholly herbaceous (that is, without 

 membranous intervals below the sinuses), not ruptured by the mature capsule; ours 



perennials, one species annual 1. Polemonium. 



Leaves simple and entire, or toothed, cleft or divided; calyx with or vrithout membranous intervals 

 below the sinuses, usually ruptured by the mature capsule (except in Collomia). 

 CoroUa strictly salverform, the tube distinctly contracted at the throat; leaves opposite (some- 

 times alternate above), entire; perennials, mostly montane 2. Phlox. 



Corolla funnelform to salverform or campanulate, the throat open. 

 Leaves alternate (rareh' some of the lower opposite). 



Leaves palmately parted, pungent, much fascicled in the axils ; undershrubs, mostly 



montane 3. Leptodactylon. 



Leaves entire or pinnately toothed, cleft or divided. 

 Calyx-lobes unequal, pungent. 



Anthers oval; bracts green or chartaceous or coriaceous, hairy or glabrous; 



annuals, mostly of summer or late spring in dry ground 



4. Navarretia. 

 Anthers sagittate; bracts mostly embedded in white wool, the lower part 

 often nearly concealed; (corolla irregular in one species) ; peren- 

 nials or annuals 5. Hugelia. 



Calyx -lobes equal, rarely pungent ; mostly annuals, some perennials. 



Calyx-sinuses distended at notch into a revolute lobe; stamens mostly un- 

 equal, unequally or equally inserted in the corolla-throat 



6. Collomia. 

 Calyx-sinuses not distended into a lobe; stamens mostly equal, mostly 



equally inserted in corolla-throat or corolla-sinuses 7. Gilia. 



Leaves opposite; corolla mostly salverform. 



Stems without proper foliage leaves, bearing at base persistent cotyledons and above 

 a whorl of involucral leaves connate at base; diminutive annuals with 



simple stems ; transmontane 8. Gymnosteris. 



Stems leafy, the leaves palmately parted or sometimes entire. 



Slender low annuals, mostly of spring; cismontane and transmontane, mostly 



of low hills or valleys 9. Linanthus. 



Perennial herbs, mostly summer-flowering; montane 10. Siphonella. 



