244 HYDRANGEACEAE (HYDRANGEA FAMILY) 



1. PHILADELPHUS L. SYBINGA. MOCK ORANGE 



Freely and divaricately branched shrubs with opposite entire leaves. Flow- 

 ers, white, showy, solitary (rarely 3), terminating the slender branchlets. 

 Calyx 4-5-parted. Petals oblong to obovate. Stamens numerous (20-60). 

 Styles 3-5, free or united; ovary inferior, 4-5-celled, becoming a dry capsule. 



Leaves small (3 cm. or less in length). 

 Leaves glabrate and shining above. 



Calyx short-hirsute 1. P. nitidus. 



Calyx glabrous . . . . . . . . . . 2. P. microphyllus. 



Leaves short-strigose on both sides . . . . . . . 3. P. occidentalis. 



Leaves large (4 cm. or more in length) 4. P. Lewisii. 



1. Philadelphia nitidus A. Nels. Bot. Gaz. 42: 54. 1906. Slenderly and 

 divaricately branched: leaves rather few, shining and with glaucous hue on 

 both sides, nearly glabrous above, minutely appressed strigose below, mostly 

 narrowly lance-oblong, subacute at both ends, very short-petioled, 1-2 cm. 

 long: flowers generally at the ends of the branchlets: calyx cleft below the 

 middle, hirsute on the outside, soft-pubescent on the inside of the lobes: 

 petals elliptic, entire, 8-10 mm. long, twice as long as the calyx-lobes: stamens 

 30^40: styles distinct down to the ovary; stigmas short, slightly geniculate 

 at junction with style. Canons of western Colorado and into Utah. 



2. Philadelphus microphyllus Gray, PI. Fendl. 54. 1848. Freely branched 

 but the branches ascending, leafy: leaves glabrous and green but somewhat 

 shining above, pale and sparsely short-strigose beneath, lance-ovate, tapering 

 to both ends, subsessile, 2-3 cm. long: flowers solitary or in 3-flowered cymes, 

 large for the plant: calyx glabrous on the exterior; the lobes softly pubescent 

 within and on the margins, elliptic, short-acuminate: petals oval, slightly 

 erose-dentate on the margins, about 15mm. long: styles united; the relatively 

 long stigmas distinct or slightly coherent. Southern Colorado and in New 

 Mexico. 



3. Philadelphus occidentalis A. Nels. Bull. Torr. Bot. Club 25: 374. 1898. 

 Divaricately and rather rigidly branched: leaves numerous, short-hirsute on 

 both sides, as are also the young twigs, oblong to ovate, subacute, with 

 rounded base: flowers terminal, solitary or in threes: peduncles and recep- 

 tacles densely white hirsute: the calyx-lobes hirsute on both faces: petals 

 obovate, 10-12 mm. long: stamens 50-60: styles united; the stigmas distinct, 

 fully half as long as the styles. Dry canons; southwestern Wyoming and in 

 Utah. 



4. Philadelphus Lewisii Pursh, Fl. Am. Sept. 329. 1814. Branching shrub 

 1-2 m. high: leaves 3-5 cm. long, short-petioled, subacute, rounded at the 

 base, glabrous or nearly so, with short ciliate incurved hairs on the margin: 

 calyx glabrous on the outside, minutely pubescent on the inside of the lobes: 

 petals oval, 12-16 mm. long: stigmas distinct and the upper part of the styles 

 only lightly coherent. Probably within our range, Montana and westward. 



2. JAMESIA T. & G. 



A diffusely branching shrub, 1-2 m. high, with opposite exstipulate serrate 

 leaves and cymose flowers in terminal panicles. Calyx-lobes 5, sometimes 

 bifid. Petals 5, obovate. Stamens 10, the alternate ones shorter; filaments 

 linear, flattened, acuminate. Ovary conical, 1-celled, with 3-5 parietal many- 

 ovuled placentae; styles 3-5. Capsule incompletely 3-5-celled, included. 

 Seeds striate-reticulate. (Edwinia Heller.) 



1. Jamesia americana T. & G. Fl. N. A. 1: 593. 1840. Leaves ovate, 

 mucronately serrate, green and glabrate above, white-canescent beneath and 

 on the petioles, 2-5 cm. long: flowers in small terminal cymes, the branchlets, 

 peduncles, and calices white-canescent: petals white, slightly hairy within, 

 7-10 mm. long, longer than the calyx-lobes (the latter enlarged in fruit). 

 Canon sides at middle elevations; Wyoming to New Mexico and west to Utah. 



