406 ROSACEAE 



about 20. Achenes inclosed in the calyx, short-stipitate, long-hairy, membran- 

 aceous, indehiscent, caducous, strongly arched on the lower suture; seeds broadly 

 oblong, with a double coat. [Holodiscus Maxim.] 



Leaves grayish- or whitish-tomentose and viUous beneath. 



Inflorescence ample, weU-compound; leaves usuallv over 3 cm. long. 



Leaf-blades abruptly contracted below, scarcely decurrent on the petioles, 4-10 



cm. long. I g discolor 



Leaf-blades cuneate at the base and distinctly decurrent on the winged petioles 

 2-5 cm. long. 2 *S duniosa 



Inflorescence small and narrow, simple, racemose, or with a few short, spreading 

 branches: leaves usually less than 2 cm. long, finely pubescent and green above, 

 white silky- villous and tomentose beneath. 3 s microphylla 



Leaves glandular-atomiferous and slightly hairy on the veins beneath, not at all tomen- 

 tose, 1-1.3 cm. long, glabrous or sparingly pubescent. 4. S. glabrescens, 



1. S. discolor (Pursh) Rydb. Shrub 1-4.5 m. high; leaf-blades rounded- 

 ovate or oval, usually double-toothed, with broadly ovate, mucronate teeth, 

 acute at the apex, truncate, rounded, or cuneate at the base, 4-10 cm. long, thin 

 green and sparingly pubescent, or in age glabrate above, more or less densely 

 Villous and tomentose beneath; inflorescence conical or ovate, 10-20 cm long 

 tmce or thrice compound; sepals oblong; petals white, elliptic, 1.5 mm. long or 

 more; stamens 15-20; pistils usually 5; carpels semi-ovate, 1-5 mm. long. Holo- 

 discus discolor (Pursh) Maxim. H. ariaefolius (Smith) Howell. Hills and river 

 banks: B.C.— Cal.— Ida.— w Mont. Submont. Je-Au. 



2. S. dumosa (Nutt.) Rydb. Shrub 6-10 dm. high; leaf-blades obovate, 



J T' :°^"' ^°^^*^ °^ ^^^*^ ^* *^^ ^P^^' oft<5n double-toothed above, green 

 and short-hairy above, white and densely villous and tomentose beneath ; inflor- 

 escence usually twice compound, ovoid, 5-20 cm. long; sepals ovate or lance- 

 ovate; petals elliptic or oval, about 2 mm. long; stamens about 20; pistils 5; 

 carpels about 1.5 mm long H. discolor (Nutt.) Heller. H. austrdlis KeWerl 

 Mountains: Wyo.— Utah— N.M.— Chihuahua. Suhrnont.—Mont. Je-S 

 «r. ^.I ^; °^^"0Phy"a Rydb. A low diffuse shrub, 3-10 dm. high; leaf-blades 



^K^„l r+l'"''''^''' ^"^-^ '^"•' '■^'i^^y, 2 '^^^ ^ong, evenly serrate above the middle, 

 obtuse at the apex, cuneate at the base; inflorescence small, 3-5 cm. long; sepals 



about 1 mm long, ovate villous; petals broadly obovate or oval, a little exceed- 



Mnimfn-^^ ^1''"'^"Tr ^' ^/^f^^ ^^°"* ^'^ ™"i- ^o^S" "■ microphyllus Rydb. 

 Jlountams. Colo.-Wyo.-Utah; apparently also in CaUf. Submont.-Mont. 



4. S. glabrescens (Greenm.) Rydb. A diffuse shrub, 6-12 dm. high; leaf- 



trnfeT^*^?!^"'^''-*^,^-!-^.^'"- l«"g' decurrent on the short petioles! evenly 

 toothed above the middle; inflorescence more or less compound; 3-6 cAi. long; 

 the branches short and spreading; sepals ovate, 1.5 mm. long; petals white, oval 



rr^J^;n &' ^ T'^"^ 20; carpels 1.5 mm. long. Spiraea discolor glabrescens 

 Oreenm. H. glabrescens KeHeT. Moimtains: Ore.-^n Calif.— Utah. 5i/6mor2<. 



■Mant. Je-Au. 



9. HORKELIA 



poi^nrJ,^^-?i.";itf fc??*^*^^^^^ leaves pinnately com- 



thium 



yj\.b.a ui cauuices. i^eaves pmnately corn- 

 Inflorescence cymose-paniculate. Hypan- 



PetTs stSihnr/^ M ""^^ to saucer-shaped. Bractlets, sepals, and petak 5. 

 kte whKr Zlf' ^bknceola e, obovate, cuneate, or obcordate often unguicu- 

 thiSm fi LpnS/.^"i°'''-^ Stamens 10, inserted in the throat of the hypan- 

 \Kir\kThTf&i t'^J'^u ""tS"' °^ '^f petaloid, persistent, triangular, iubu- 

 numeroiS nist Is It.X ^^^ ^^^^P^^j^ g^^eraUy conic or hemispheric, with 



anatropoug. 



mm. ] 

 6 mm 



fcUets obovate or cuneate, usually 

 inflorescence. 



1. H. parviflora, 



'■ inflorescence. 



2. II. capitata. 

 shorter than the 



3. if. fusca. 



