96 



KEY TO THE FAMILIES AND GENERA 



71. ROSACEA. 

 /. Summary of Tribes, 



,. Ovary inferior: carpPls 2-5. more or 

 less ciMinato and atinate to the cup- 

 shaiHnl receptacle, the whole develop- 

 ing into a lleshy fr. (pome): trees or 



shruhs with frve s^tipules 4. Pome Tribe. 



I. Ovar>' superior. 

 B. Carpels usuaUy many, if 1 or 2, fr. 

 not (Irupaeeous: calyx persistent. 

 c. Fr. folhcular. dfhiscent. 



D. Seeds not winwed: Hs. small 1. SpiR-ea Tribe. 



DD. Seeds winged, flattened: fla. 



rather large 2. Quillaja Tribe. 



cc. Ft. not follicular, indeliiseent, or 

 carpels growing itito drupelets. 

 D. Pistils borne on a flat, hemi- 

 spherical or convex receptacle, 

 subtended by a cup-shaped 

 portion of the receptacle (hy- 

 panthium), usually many. 

 E. The pistils 2-5: shrubs, with 

 simple Ivs. 

 F. Stipules wanting: fls. small, 



in large panicles 3. Holodiscus 



FT. Stipules present: fla. soli- Tribe. 



tary or in few-fid. 



corymbs 5. Kerria Tribe. 



EE. The pistils many (if few, Ivs. 



compound ) : herbs or shrubs. 



F. C a r p el s becoming dry 



achenes. 



G. Ovules 2: carpels 5-15: 



calyx without bractlets: 



herbs 9. Ui.maria Tribe. 



GO. Ovules 1: carpels many; 

 calyx usuaUy with 

 bractlets alternating 



with the lobes 6, Potentilla 



FT. Carpels becoming drupelets: (Tribe. 



ovules 2. but seed solitary. 7. RuBUa Tribe. 

 DD. Pistils inclosed in the tubular- 

 or urn-shaped receptacle (hy- 

 panthium). 

 E. Number of pistils 1 or 4; 

 petals sometimes wanting. 

 F. Hypanthium tubular or cam- 

 panulate. the achenes 

 loosely and usually only 

 partly inclosing; pistils 



usually 1: shrubs S. Cercocarpus 



FF. Hypanthium urceolate. com- [Tribe. 



pletely inclosing the 1-4 

 achenes; sepals usually 4: 



herbs or shrubs 10. Sanguisorba^ 



EE. Numberof pistils many; calyx- [Tribe. 

 tube becoming fleshy; petals 

 present : shrubs with odd- 

 pinnate Ivs 11. Rose Tribe. 



BB. Carpels 1, rarely 2: fr. drupaceous: 

 calyx usually deciduous. 

 c. Fls. symmetrical; style subter- 

 minal: ovules pendulous; radicles 



superior 12. Prunus Tribe. 



cc. Fls. often unsymmetrical; style 

 basilar: ovules ascending; 



radicles inferior 13. Chrvsobalanus 



[Tribe. 



//. Key to the Tribes. 



1. Spiraea Tribe. 



A. Kstils opposite to the petals or less than .5. 



B. Lv8. simple, often lobed, rarely pinnatifid: 



stamens inserted on the margin of the 



hypanthium: shrubs, rarely undershnibs. 



c. Stipules large, caducous: staminal disk 



wanting: seeds shining, crustaceous. 



D. J'oUicles dehL-cent along both sutures, 



often inflated. 1-5: fls. in terminal 



corymbs 1. Phyaocarp- 



DD. Follicles dehiscent only along the ven- [ua, 



tral suture, 1-2, not inflated. 

 E. Fls. in terminal panicles; style ter- 

 minal; pistils, 2. rarely 1: follicles 



usually .5-Heeded 2. Neillia. 



EE, Fls. in small U;rminal corymbs; style 

 lateral; pistil 1: follicles 1-or rarely 



2-»eedcd 3. Stephannn- 



cc. Stipules wanting: staminal disk usually [dra. 



prenent: seeds dull. 

 r. The Ivs. entire, serrate or lobed: sta- 

 meofl free. 

 E. Carpels free. 



F. Fls. in panicles, corymbs or umbel- 

 like racemes; carpels dehuscent 

 along the ventral suture: Ivs. 

 usually serrate or lobed 4. Spiraia. 



FF. Fls. in rncemes; carpels dehiscent 

 on both sutures: Ivs. entire, 

 evergreen; cespitose undershrvib. 5. Prtrophy- 

 ee. Carpels connate at the base; Hs. poly- [turn, 



gamo-tlirt'cious, in panicles: Ivs. 

 entire, deciduous: upright shrub. . . G. Sibirsea 

 DD. The Ivs. twice trilid:stamenscoimateat 

 the base: fls. in racemes: prostrate 



undcrshrub 7. Luetkea. 



BB. Lvs. 2-3-pinnatc: fls. dioecious, in ample 

 I)anicles composed of slender spikes: 



herbs 8. Aruncus. 



AA. Pistils opposite to the sepals, 5. 



D. Petals roundish, imbricate in the bud; car- 

 pels connate at the base: lvs. pinnate or 

 bipinnate: shrubs. 



c. Lvs. pitiiiuti-; Ifis. coarsely serrate 9. Sorbaria. 



cc. Lvs. Iii]>inn;it('; scgms. minute, entire 10. Chamxbati- 



BB. Petals .strap-sh:iped, convolute in the bud: [aria. 



carpels distinct: lvs. ternate: herbs H. Gillenia. 



2. Quillaja Tribe. 



K. Carpels free, spreading, star-like at maturity: 

 evergreen trees. 



B. Stamens 10 12. Quillaja. 



BB. Stamens 20 13. Kageneckia, 



aa. Carpels connate into a 5-celled caps.: sta- 

 mens 15-20: deciduous shrub 14. Exochorda. 



3. Holodiscus Tribe. 



Lvs. doubly serrate or slightly lobed 15. Holodiscus. 



4. Pome Tribe. 



A. Carpels bony at maturity; fr* hence with 1-5 

 stones. 

 B. Pistils with 2 fertQe ovules: Iva. entire or 

 crenate. 

 c. Lvs. entire: spineless shrubs: styles 2-5. . . 16. Cotoneaater. 

 cc. Lvs. crenate, persistent: usually spiny 



shrubs: styles 5 17. Pyracantha. 



BB. Pistils with only 1 fertile ovule: lvs. usually 

 doubly serrate or lobed. 

 c. Ovules 2, 1 fertile and 1 sterile: lvs. sim- 

 ple, often pinnately lobed. 

 D. Number of carpels 5, wholly connate 

 and covered at the top by the flesh of 

 the fr.: fls. solitary, 2 in. across: lvs. 



entire or occasionally dentate . 18. Mespilua. 



DD. Number of carpels 1-5, more or less dis- 

 tinct at the ventral suture and free at 

 the top: fls. 1 in. or less across, usually 



in corymbs: lvs. often lobed 19. Cralsegua. 



cc. Ovule but 1; stones 5: lvs. pinnate (the 

 simple-lvd. species belong to Hespeco- 



meles, which is not in cult.) 20. OsteomeUa. 



AA. Carpels with leathery or papery walls at 

 maturity: fr. hence l~5-celled, each cell with 

 1 or 2, rarely many seeds. 

 B. Fls. in compound corymbs. 



c. Styles 1-5, distinct or connate; carpels 

 partly free. 

 D. Fr. solid and pointed at the top; walls 

 of cells leathery: lvs. deciduous, sim- 

 ple or pinnate. 

 E. Sepals deciduous: lvs. always simple, 

 serrate with excurrent veins: styles 



2-3 21. MicTOmeles. 



EE. Sepals persistent. 



F. Number of styles usually 2, rarely 3 

 or 5, free or connate: lvs. pin- 

 nate or simple and serrate or 

 lobed with excurrent veins, 



deciduous 22. Sorhua. 



FF. Number of styles 3-5: lvs. serrate 



to crenulate, with curving veins. 



G. Lvs. deciduous, with glands on 



the midrib above: styles 5, 



connate below: endocarp thin. 23. Aronia. 



UG. Lvs. evergreen, without glands 



on the midrib: styles 3-5: 



endocarp firm 24. Stranvaeaia. 



DD. Fr. hollow and rounded at the top, 

 small, l-or2-seeded; walls usually pa- 

 pery: styles u.sually 2: lvs. simple, 

 deciduous or evergreen with curving 



veins 25. Phoiinia. 



cc. Styles 5. distinct; carpels wholly connate: 

 fr. pear-shaped, rather large, yellow: 



lvs. evergreen with excurrent veins 26. Erioboirya. 



BB. Fls. in umbels, racemes or solitary. 

 c. The carpels 4- to many-seeded. 



D. Styles free: lv.s. entire 27. Cydonia. 



DD. Styles connate at the base: lvs. serrate 

 or serrulate. 

 e. Ovules many in each cell: calyx gla- 

 brous outside 28. ChxnomeUs. 



EE. Ovules 4-5 in each cell; calyx densely 



tomentose outside 29. Docynia. 



cc. The carpels l~2-seeded. 



