96 



KEY TO THE FAMILIES AND GENERA 



71. ROSACES. 

 /. Summary of Tribes. 



A. Ovary inferior; carpels 2-5, more or 

 less connate and adnate to the cup- 

 shaped receptacle, the whole develop- 

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



shrubs with free stipules 4 p OM E TRIBP 



AA. Ovary superior. IBB! - 



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

 not drupaceous: calyx persistent. 



C. Fr. follicular, dehiscent. 



D. Seeds not winged: fls. small. ... 1. SPIRAEA TRIBE. 

 DD. Seeds winged, flattened: fls. 



r*o T3V I a 7 le r , 1 ar *?' -.;, 2. QuiLLAJA TRIBE. 



cc. Fr. not folhcular, mdehiscent, or 

 carpels growing into 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. HoLODiscns 



FF. Stipules present: fls. soli- TRIBE 



tary or in few-fld. 



__ T . corymbs 5. KBRHIA TRIBE. 



EE. J.ne pistils many (if few, Ivs 



compound) : herbs or shrubs. 



F. C a r p el s becoming dry 



achenes. 



o. Ovules 2; carpels 5-15: 

 calyx without bractlets: 



herbs 9. ULMARIA TRIBE. 



00. Ovules 1: carpels many; 

 calyx usually with 

 bractlets alternating 



with the lobes 6. POTENTILLA 



FF. Carpels becoming drupelets: [TRIBE 



D.- -i o.vu'es 2 , but seed solitary. 7. ROBUS 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 8. CEHCocARptjg 



FF. tlypantnium urceolate, com- (TRIBE 



pletely inclosing the 1-4 

 achenes; sepals usually 4: 



... XT t y ibs T . sh , rab8 10. SANGCISORBA 



EE. Number of pistils many; calyx- [TniBE 



tube becoming fleshy; petals 



present: shrubs with odd- 



P.^,1 P innat f lv - v 11. ROSE TRIBE. 



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

 calyx usually deciduous, 

 c. Fls. symmetrical; style subter- 

 minahovules pendulous; radicles 



. fi supe fi or 12. PRUNUS TRIBE. 



cc. Fls. often unsymmetrical; style 

 basilar: ovules ascending- 

 radicles inferior 13. CHHYSOBALANUS 



[TRIBE. 



//. Key to the Tribes. 

 1. Spiraea Tribe. 



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

 B. Lvs. simple, often lobed, rarely pinnatifid- 

 stamens inserted on the margin of the 

 hypanthium: shrubs, rarely undershrubs. 

 c. btipules large, caducous: staminal disk 

 wanting: seeds shining, crustaceous. 



D. follicles dehiscent along both sutures 



often inflated, 1-5: fls. in terminal 



DD. FoTliclS dehisceni'oniy'along't'he'ven: *' Phusocar P- 

 tral suture, 1-2, not inflated. 



E. *ls. in terminal panicles; style ter- 



minal; pistils, 2, rarely 1: follicles 



usually 5-seeded 2 Neittia 



EE. Fls. in small terminal corymbs; style ' 

 {^eraljjjistil 1: follicles 1-or rarely 



<j m 



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

 mens free. 

 E. Carpels free. 



F. Fls. in panicles, corymbs or umbel- 

 like racemes; carpels dehiscent 

 along the ventral suture: Ivs 

 usually serrate or lobed 4. Spirxa 



FP. Fls. in racemes; carpels dehiscent 

 on both sutures: Ivs. entire, 



PP r evergreen: cospitose "ndershrub. 5. Petrophy- 

 EE. Carpels connate at the base; fls. poly- \ tum 



gamo-dicecious, in panicles: Ivs 



nr. Tl, n 1 ntlr , ei . decic ! us: upright shrub. . . 6. Sibirxa 

 DD. The Ivs. twice trind: stamens connate at 

 the base: fls. in racemes: prostrate 



undershrub 7 r , ,. 



BB. Lvs. 2-3-pinnate: fls. dioecious; 'in ample 

 panicles composed of slender spikes: 



AA. Pistils op S posi'te'to' the sepals,' 5.' S ' Aruncui - 



B. Petals roundish, imbricate in the bud- car- 

 pels connate at the base: Ivs. pinnate or 

 bipinnate: shrubs. 

 c. Lvs. pinnate; Ifts. coarsely serrate . . . . 9 Sorbaria 



P ^ V ?' bl P mnatc : ""Sms. minute, entire 10. Cham a- 



BB. Petals strap-shaped, convolute in the bud- 

 carpels distinct: Ivs. ternate: herbs 11. Gitlenia. 



2. Quillaja Tribe. 



n. Carpels free, spreading, star-like at maturity 

 evergreen trees. 



B. Stamens 10 )9 r. . 



BB. Stamens 20. ' to" { *. utUa J a - . 



AA. Carpels connate into' a 'o-eeil'ed 'cap's'.:' 's't'a- ' 



mens 15-20: deciduous shrub 14. Exochorda. 



3. Holodiscus Tribe. 

 Lvs. doubly serrate or slightly lobed 15. Holodiicua. 



4. Pome Tribe. 



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



stones. 

 B. Pistils with 2 fertile ovules: Ivs. entire or 



crenate. 



c. Lvs.entire:spinelessshrubs:styles2-5. . . 16. Cotoneasier. 

 sh C b re ' P erslsten ': usually spiny 



BB. Pistil, with onfyl fertile ovule:' Ivs. usually 17 ' Pvracantha - 



doubly serrate or lobed. 



c. Ovules 2, 1 fertile and 1 sterile: Ivs. 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: Ivs 



entire or occasionally dentate 18. Mesmlus 



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: Ivs. often lobed... 19 Cratseaus 



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

 simple-Ivd. species belong to Hespeco- 

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



AA. Carpels with leathery or papery walls at 

 maturity: fr. hence 1-S-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: Ivs. deciduous, sim- 

 ple or pinnate. 



E. Sepals deciduous: Ivs. always simple, 

 serrate with excurrent veins: styles 



23 21 \fifr f 



EE. Sepals persistent. 



F. Number of styles usually 2, rarely 3 

 or 5, free or connate: Ivs. pin- 

 nate or simple and serrate or 

 lobed with excurrent veins 



deciduous. . 2 2. Sorbun. 



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

 to crenulate, with curving veins. 

 G. Lvs. deciduous, with glands on 

 the midrib above: styles 5, 

 connate below: endocarp thin .23. Aronia 

 GG. Lvs. evergreen, without glands 

 on the midrib: styles 3-5: 

 endocarp firm. .. 24 SVr>,>->a,v. 



DD. Fr. hollow and rounded at'the top, 

 small, 1- or2-seeded ; walls usually pa- 

 pery: styles usually 2: Ivs. simple, 

 deciduous or evergreen with curving 



cc. Styles 5, distinct'; 'carpels wholly connate': ' '"" o> 

 fr. pear-shaped, rather large, yellow 



Ivs. evergreen with excurrent veins 26. Eriobotrya. 



BB. Fls. in umbels, racemes or solitary, 

 c. The carpels 4- to many-seeded 



D. Styles free: Ivs. entire 2 7. Cydonia. 



DD. Styles connate at the base: Ivs. serrate 

 or serrulate. 



E. Ovules many in each cell: calyx gla- 



brous outside ' 28 Chxnomelea 



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



tomentose outside... 2 q /),.,,, 



cc. The carpels 1-2-seeded. 



