1700 



SPIR.EA 



SPIRAEA 



KEY TO THE SECTIONS. 



A. Lvs. always entire: fls. in simple or panicled 

 racemes: follicles usually IB-seeded. (Bo- 

 tryospira, Zabel.) 

 B. Plants tufted, suffruticose: fls. perfect, in 



usually simple racemes 



Section 1. Petrophytum (Species not in cult. ) 

 bb. Plant an upright shrub with stout branches: 



fls. polygamous in panicled racemes 



Section 2. Sibir^ea (Species No. 1) 

 AA. Lvs. usually serrate, rarity entire: fls. in 

 umbel-like racemes, corymbs or panicles: 

 seeds several. 

 b. Inflorescence a simple umbel-like raceme: 



fls. white 



Section 3. Cham-edryon (Species Nos. 2-20) 

 bb. Inflorescence compound: fls white or pink. 



c. Pis. in corymbs 



Section 4. Calospira (Species Nos. 21-36) 



CC Fls. in panicles 



Section 5. Spiraria (Species Nos. 37-49) 

 index. 

 acuta, 2. cuneata, 21. Nobleana, 42. 



aeutifolia, 2. cuneifolii, 21. notha, 39. 



adiantifolia, 13. deeuuibens. 22. nova, 16. 



alba. 37, 44. densiflora, 36. oblongifolia, 19. 



albiflora, 31. Douglas!, 48. obovata, 2. 



alpina, 8. eximia, 47. - ovata, 24. 



Altaica,!. expansa, 25. pachystachys, 42. 



aquilegifolia, 13. flabellata. 2. paniculala, 38, 44. 



arbuscula, 36. flagellata, 21. Pikowiensis, 10. 



argentea, 21. flagelliformis, 21. proctunbens, 22. 



arguta, 4. flexuosa, 20. pruinosa, 37. 



atrifolia, 20. Fontenaysii, 37. prcinifolia, 6. 



atrosanguinea, 27. Fontanaysicnsis,37. pubescens. 17, 18, 27. 

 auhifolia, 20. Fortunei, 27. pulehella. 25. 



bella, 24. Fnxii, 29. pumila, 30. 



liethlehemensis. 45, glabrata, 27. pyramidata, 40. 



47. glabreseens, 10. Reevesiana, 15. 



betulifolia, 35. granditlora, 43 and Regeliana, 41. 



Billardii, 47. suppl. robusta, 16. 



blanda, 16. hypericifolia, 2. rosea, 36. 



Blumei, 12, 13. intermedia, 41. rotunditolia, 11. 21. 



brachybotrys, 37. Japonica, 27 and mberrima. 27, 30. 



braeteata, 11. suppl. rupestris, 12. 



bullata, 26. Japonica alba, SI. salieit'olia, 43, 44, 



Bumalda, 30. Japonica panicu- 45. 



Californica, 47. lata, 38. Sanssoueiana. 41. 



callosa, 27. Kumaonensis, 25. seraperflorens, 38. 



cana. 7. laevigata, 1. serieea, 19. 



Canadensis, 45. lanceolata, 15, 44. Sibirica, 43. 



caneseens, 21. latifolia, 45. superba, 32. 



Cantoniensis, 15. Lemoinei, 30. syringreflora, 38. 



carnea, 43. Lenneana, 47. thalictroides, 2, 



carpinifotia, 45. leucantha, 31. Thunbergii, 3. 



chamsedryfolia, 20. longigemmis, 23. tomentosa, 49. 



Chinensis, 17. lucida, 34. triloba, 13. 



coccinea, 24. luxuriosa, 37. trilobata, 13. 



confusa, 19. macrophylla, 27. triumpbans, 47. 



conspieua, 38. Margaritre, 28. truncata, 2. 



Constantly, 47. media. 11, 19. ulmifolia, 20. 



corymbosa, 15, 33. Menziesi, 46. vaccinifolia, 21 and 



cratcegifolia, 13, 33. multifiora, 5. suppl. 



crenata, 2, 9. Nicoudierti. 10. Van HouJtei, 14. 



crenifolia, 9. Nipponica, 11. Virginiana, 34. 



crispifolia, 26. 



Section 1. Petrophytum (Species not in cult. ). 



This section contains a few rather rare American spe- 

 cies of which none is in cultivation. The best known 

 is S. caespitosa, Nutt. (Petrophytum ccespitdsum,' 

 Rydb.), a dwarf cespitose subshrub, only a few inches 

 high, with crowded, small, entire Its. and small, whitish 

 fls. in dense, usually simple racemes on slender stalks 

 arising from the tufts of the grayish green foliage. It 

 is very unlike any other Spirea and more resembles in 

 habit a Saxifraga. It is perhaps better regarded as a 

 distinct genus like the allied Kllseya unifldra, Rydb. 

 (Eriogynia unifldra, Wats.), and Eriogynia peetiniitu. 

 Hook. 



Section 2. Sibirjea (Species No. 1). 



1. laevigata, Linn. | S. Altaica, Pall. Sibircea Icevi- 

 gAta, Maxim.). Shrub, 5 ft. high, with stout upright 

 branches : lvs. cuneate-oblong, bluish green, glabrous, 

 l%-3% in. long: fls. polygamous, greenish white in 

 terminal panicles, .1-5 in. long, those of the staminate 

 plant somewhat showier. May. Siberia. — Hardy. 



Section 3. Chajledryon (Species Nos. 2-20). 



A. Pis. in sessile umbels, with none 

 or very small lvs. at the base or 

 only the lower umbels on leafy 

 stalks. 

 B. Foliage entire or crenately den- 

 tate only near the apex, often 



S-nerved, grayish green 2. hypericifolia 



bb. Foliage dentate or serrate, usu- 

 ally penninerved, bright 

 green. 

 O. Shape of lvs. linear-lanceo- 

 late: glabrous 3. Thunbergi 



CC. Shape of lvs. ovate to oblong- 

 lanceolate : finely pubes- 

 cent when yon mj. 

 D. Umbels on the lower part 

 of the branches stalked. 



E. Lvs. oblong 4. arguta 



ee. Lvs. obovate 5. multitlora 



dd. Umbels all sessile, SS-f/d. 6. prunifolia 

 AA. Fls. in umbel-like racemes on 

 leafy stalks. 

 b. Margin of lvs. entire or crenate 

 or dentate only toward the 

 apex. 

 C. Foliage grayish pubescent 



on both sides 7. cana 



CC. Foliage almost glabrous. 

 D. Shape <>f lvs. elliptic to 

 Oblong-lanceolate. 

 E. Lvs. p e n n i n er v e d : 



shoots angular 8. alpina 



EE. Lvs. all or partly 

 S-nerved. 

 F. Shoots striped: lvs. 



all S-nerved 9. crenata 



FF. Shoots terete: lvs. 

 partly penninerved, 



partly S-nerved 10. Pikowiensis 



DD. Shape of lvs. almost or- 

 bicular, 3 . t -l in. broad. .11. braeteata 

 BB. Margin of Irs. ineiseh/ serrate 

 and often slightly lobed {only 

 in No. 19 sometimes entire). 

 C. Stamens shorter than or as 

 long as petals: sepals 

 erect or spreading in 

 d. Foliage glabrous. 



E. Form of lvs. orbicular 

 to ovate. 

 F. Apex of lvs. obtuse. 

 o. Lv s. penninerved, 



ovate 12. Blumei 



go. Lvs. pa I mutely 3-5- 



nerved, orbicular. l.'t. trilobata 

 ff. Apex of lvs. acute. ..14. Van Houttei 

 ee. Form of lvs. rhombic- 

 lanceolate 15. Cantoniensis 



DD. Foliage pubescent, at least 

 beneath. 

 E. Umbels and follicles 

 pubescent. 



F. Tomentnm grayish . .10. blanda 

 ff. Tomentnm yellowish. 17. Chinensis 

 EE. Umbels and follicles 



glabrous 18. pubescens 



CC. Stamens longer than petals: 

 sepals re flexed. 

 D. Shoots terete, often pubes- 

 cent in fruit 19. media 



dd. Shoots angular, glabrous. 20. chamaedryfolia 



2. hypericifolia, Linn. Vigorous shrub, 5 ft. high, 

 with slender arching or upright branches: lvs. almost 

 sessile, cuneate-obovate to obovate-lanceolate, 3-nerved 

 or with few lateral veins, almost glabrous, S A-VA in. 

 long: fls. small, white, in sessile umbels; pedicels usu- 

 ally pubescent; petals almost orbicular, usually longer 

 than stamens. April, May. S. E. Eu. to Siberia. — Va- 

 riable species. Var. acutifdlia, Vi'enzig (S. acutifdlia, 

 Willd. <S. hypericifolia, var. acuta, Ser.). Lvs. nar- 



