(ENOTHERA 



(ENOTHERA 



2329 



greater number of the species are of only secondary 

 importance to the cultivator. Amongst the best of the 

 border-plant species are (E. fruticosa var. Youngii, (E. 

 linearis, (E. pratensis, (E. glauca var. Fraseri, (E. 

 csespitosa, (E. missouriensis, (E. speciosa. There are 

 numbers of showy species in the genus, and others than 

 those here accounted for may be expected to appear in 

 cult. In recent years, the genus has assumed unusual 

 interest because of the de Vriesian studies of evolution, 

 founded on the mutations or elementary species in 

 the Onagra group. 



The cenotheras are of wide distribution in North 

 America. They are open-ground sun-loving plants. 

 Many of them are prominent plants of the prairies and 

 plains. Some of them grow on the seacoasts and others 

 in moist ground, but they are not marsh plants. The 

 several widespread field species, the dead stalks of 

 which, with the split upright pods (Fig. 2566), are con- 

 spicuous in pastures and on roadsides, are grouped 

 together in current floras under the name G?. biennis, 

 but show great diversity among themselves. They are 

 not ornamental plants, although the flowers that open 

 first are usually rather large and attractive. The plants 

 of the subgenus Kneiffia afford the sundrops of gardens; 

 these cultivated plants are not well understood botan- 

 ically, and it is not unlikely that some of them are 

 hybrids or mutants. 



There is nothing special to say about the culture of 

 cenotheras except to note the tender kinds and the 

 biennials. All do well in ordinary garden soil, enjoying 

 sunshine. They are easily raised from seeds and cut- 

 ings. (E. acaidis, (E. csespitosa are low-growing bien- 

 nials which do well treated as annuals. They will not 

 endure the winter. (E. missouriensis is an excellent 

 trailer, with enormous yellow flowers and seed vessels. 

 It is quite hardy, and a fine rock-garden plant. (E. 

 biennis, the common evening primrose, is rather weedy, 

 and fit only for the wilder parts of the garden. (E. 

 Lamarckiana is a better form. (E. fruticosa and 

 (E. Fraseri are two of our best border kinds, with 

 stiff branching stems. (E. linearis is a pretty little 

 species, often naturalized but well worth growing. 

 Child's Mexican primrose is tender, but makes a pretty 

 plant for hanging-pots. (E. speciosa is a fine species, 

 but spreads so quickly by underground stems as to 

 become a weed in favorable situations: it is good for 

 naturalizing in wild grounds. (T. D. Hatfield.) 



Bcaulis, 20. 

 albicaulis, 8, 9. 

 Allenii, 15. 

 biennis, 5. 

 bistorta, 2. 

 brachycarpa, 22. 

 brevistylis, 6. 

 caspitosa, 21. 

 californica, 9. 

 cheiranthifolia, 3. 

 Childsii, 18. 

 Drummondii, 7. 

 francascana, 5. 

 Fraseri, 12. 

 fruticosa, 13, 15. 



INDEX 



ffigas, 6. 

 glauca, 12. 

 grandiflpra, 5. 

 Havardii, 11. 

 hirsutissima, 5. 

 Lamarckiana, 5. 

 lata, 6. 

 linearis, 15. 

 macrocarpa, 10. 

 major, 13. 

 mexicana, 18. 

 missouriensis, 10. 

 nanelly,, 6. 

 oblonga, 6. 

 ovata, 1. 



pattida, 15. 

 Pilgrirnii, 14. 



pinnatifida, 8. 

 pratensis, 16. 

 pumila, 14. 

 rosea, 18, 19. 

 rubricalyx, 6. 

 rubrinervis, 6. 

 serrulata, 4. 

 speciosa, 17. 

 taraxacifolia, 20. 

 tetraptera, 18. 

 Veitcniana, 2. 

 Youngii, 13. 



KEY TO THE GROUPS OR SUBGENERA. 



A. Stigma capitate or disk-like, entire. 



B. Calyx-tube filiform I. TARAXIA, No. 1 



BB. Calyx-tube short, obconic or funnelform 



II. SPH.EROSTIGMA, Nos. 2, 3. 

 AA. Stigma deeply 4-cleft or at least J^-toothed. 

 B. Stamens of equal length. 



c. Calyx-tube shorter than the ovary 



III. MERIOLIX, No. 4. 

 cc. Calyx-tube usually much exceeding the ovary. 



D. Seeds angled, horizontal in the pod 



IV. ONAGRA, Nos. 5, 6. 

 DD. Seeds not angled, ascending. 



E. Fls. yellow, erect in bud: seeds in 2 rows 



in each locule V. RAIMANNIA, No. 7. 



EE. Fls. white or pink, drooping in bud: 



seeds in 1 row VI. ANOGRA, Nos. 8, 9. 



BB. Stamens of unequal length, 

 c. Plant caulescent (with st.). 

 D. Fls. yellow. 



E. Seeds crested. VII. MEGAPTERIUM, Nos. 10, 11. 



EE. Seeds not crested. 



VIII. KNEIFFIA, Nos! 12-16. 



DD. Fls. white, pink or reddish 



IX. HARTMANNIA, Nos. 17-20. 

 cc. Plant stemless. 



D. Caps, with wrinkled wing-angles 



X. PACHYLOPHUS, No. 21. 

 DD. Caps, with plane or entire wing-angles .... 



XI. LAVAUXIA, No. 22. 



I. SUBGENTTS TARAXIA. 



Stemless, usually perennial: stigma capitate; calyx-tube 

 filiform: caps, sessile, narrow to ovate, usually not 

 winged: fls. yellow. 



1. ovata, Nutt. GOLDEN EGGS. Perennial: Ivs. 

 slightly pubescent, ovate to lance-oblong, 8 in. or less 

 long, acute, serrulate or entire: fls. yellow; petals about 

 ^in. long, orbicular; calyx-tube filiform, 3-4 in. long; 

 fl.-bud erect: caps, to 1 in. long, more or less subter- 

 ranean. Calif. 



H. SUBGENUS SPH^EROSTIGMA. 



St.-bearing: stigma capitate; calyx-tube short, inversely 

 conic or funnelform: caps, sessile, linear, not 

 winged: fls. various. 



2. bist6rta, Nutt. One to 2 ft., the base decumbent, 

 hairy and pubescent: radical Ivs. spatulate to lanceo- 

 late and petiolate, dentate; st.-lvs. mostly sessile- 

 ovate to narrow-lanceolate and about 1 in. long, den- 

 tate: fls. yellow, turning green, the petals (about J/in. 

 long) usually with a brown spot at the base; calyx-tube 

 1-3 in. long: caps. %in. or less long, 4-angled, con- 

 torted. S. Calif. 



Var. Veitchiana, Hook. More slender: radical Ivs. 

 narrow-oblanceolate and long-petioled: caps, longer 

 and narrower (1-1J^ in. long) and little contorted. 

 S.Calif. B.M. 5078. 



3. cheiranthifSlia, Hornem. Sts. decumbent or 

 ascending, 2 ft. or more tall, canescent : Ivs. thick, about 

 1-2 in. long, broad-ovate to oblanceolate or the lower 

 ones spatulate, the upper ones becoming sessile, most of 

 them entire: petals yellow, M~M m - long: caps. %in. 

 or less long, curved or spiral, somewhat hairy. Calif. 

 B.R. 1040. 



m. SUBGENUS MERIOLIX. 



St.-bearing: stigma disk-like but 4-toothed; calyx-tube 

 shorter than the ovary, enlarging upward: caps, 

 linear or nearly cylindrical, sessile: fls. yellow, 

 axillary. 



4. serrulata, Nutt. (Meriolix serrulata, Walp.). 

 Biennial or perennial: slender, simple or branched, 

 about 1 ft. high but variable in stature, nearly glabrous 

 to canescent: Ivs. linear to lanceolate, 1-3 in. long, 

 usually acute, attenuate to the base, sharply dentate: 

 petals broad-obovate, J^in. long, wavy-margined. 

 Minn., west and south. Mn. 7:41. 



IV. SUBGENUS ONAGRA. 



St.-bearing: stigma J^-deft; calyx-tube elongated and 

 cylindrical, enlarging at the throat: caps, linear- 

 oblong to long-conic, ^-angled: fls. yellow, opening 

 in evening. TRUE EVENING PRIMROSES, com- 

 prising a mutating group. 



5. biennis, Linn. (Onagra biennis, Scop.). EuROr 

 PEAN EVENING PRIMROSE. Fig. 2566. Usually bien- 

 nial, but often flowering the first year: mature rosettes 

 of plants grown in rich soil 2 ft. diam.: roots large and 

 fleshy, often 2 in. diam. at the crown: st. about 34 ft. 

 tall, copiously branched, green: Ivs. varying from nar- 

 rowly oblanceolate below to ovate above: calyx-tube 



