110 



ASCLEPIADACEAE 



Locs. — The plants of the Soiith Coast Eanges are taken as exactly representative of Asclepias 

 erioearpa Benth. We find also through the North Coast Eanges and Sierra Nevada foothills in 

 dry flats and summer flood beds of ■winter streams a milkweed which is extremely uniform in char- 

 acter and agrees in every particular with the plants of the South Coast Eanges just noted: in 

 habit, in aspect, in foliage, in iufloreseeuce, in every detail of the flowers and in fruits. It seems 

 unlikely, therefore, that there exists in the Sacramento Valley region a lost species, A. fremontii 

 Torr., with definitely differentiating characters. Specimens of the North Coast Eanges distrib- 

 uted as Asclepias fremontii by W. W. Eggleston, who made special field studies of this species, 

 agree quite in details of flower structure with the type of A. erioearpa Benth. (Kew, W. L. J. 

 1906). Later, Eggleston concluded his studies, arrived at the same conclusion and in 1926 made 

 verbally the statement : "There is no difference in flowers between Asclepias fremontii and A. erio- 

 earpa. None at all." (Jepson Field Book, 44:180. ms.). As a matter of ecological consideration 

 it is probable that neither Asclepias erioearpa, nor any form of it such as A. fremontii, is properly 



a dweller in humus soils on the flood-plain floors of the 

 Sacramento Valley. Asclepias erioearpa is known in the 

 valley thus far only in gravel beds or on terraces or 

 benches of streams as a waif from the hills, or as occur- 

 ring on higher ground about the MarysvUle Buttes, a hUly 

 "island" set in the floor of the plain, or in clay or adobe 

 situations. In support of the general range of Asclepias 

 erioearpa in California we cite the following localities. 

 Sierra Nevada : Payne Creek, Tehama Co., Jepson 12,342 ; 

 Oroville (foothills e.). Heller 11,573; Nevada City, Jep- 

 son. 16,766 ; Shaver Lake ranger sta., Fresno Co., Jepson 

 10,101 ; Three Elvers, Jepson 563. Tehachapi Mts, 

 Double Mt., Jepson 7424. Sacramento Valley: Bedding, 

 BlanTcinship : Jelleys Ferry, Tehama Co., Jepson 18,985 

 Marysville Buttes; Dunnigan, Yolo Co., Jepson 12,251 

 Coast Eanges : Eound Valley, ne. Mendocino Co., Jepson 

 Long Valley, cent. Mendocino Co., Jepson 9446 ; IJkiah 

 Jepson 2253; Big Valley, Lake Co., Jepson 14,535 

 Knights Valley, Sonoma Co., Jepson 7433 ; Pope Creek 

 e. Napa Co., Jepson 14,536 ; Soda Creek (5 mi. s. of Mon 

 ticello), e. Napa Co., Jepson 17,654; Putah Pass, Jepson 

 14,534; Stone Canon, e. Monterey Co., Jepson 15,920; 

 Soledad, Monterey Co., Congdon; Cold Spr., near Posts, 

 Santa Lucia Mts., Jepson 2599 ; Naeimiento Elver val- 

 ley, Jepson 1700. S. Cal.: Mono Flat ranger sta., Santa 

 Barbara Co., A. L. Grant 1743; Ojai Valley, Olive 

 Thaeher 32 ; Eubio Canon, San Gabriel Mts., Feir'son 148 ; 

 Cajon Pass, Jepson 6100; San Bernardino, Parish; 

 Santa Ana Canon, Orange Co., /. T. Howell 2785; Santa 

 Eosa Mts., Clary 120S ; Palomar Mt., S. G. Stokes ; Escon- 

 dido, C. V. Meyer 447; Things Valley (15 mi. n. of 

 Campo), Parish 1930. 



Var. microcarpa M. & J. Follicles short (1% to 1% 

 inches long). — San Bernardino Mts., 6000 feet. 

 Eefs. — AscLEPLiS ERIOCARPA Benth., PI. Hartw. 323 (1849), type loc.Tulareitos,nw. Monterey 

 Co., Hartweg 127; Jepson, Fl. W. Mid. Cal. 383 (1901), ed. 2," 323 (1911), Man. 772 (1925) 

 A. fremontii Torr.; Gray, Syn. Fl. 2:93 (1878), type loe. "upper Sacramento," Fremont (i.e 

 Marysville Buttes, ace. W. W. Eggleston) ; McCumber, MoCIoud Eiver, Neivberry (Pae. E. Eep, 

 6:87,-1857) ; Jepson, Fl. W. Mid. Cal. 383 (1901), ed. 2, 323 (1911), Man. 773 (1925). A. lo 

 ioJoEastw., Zoe5:86 (1900), 98 (1901), tj-peloa.VMah, J. M. Hudson. Var. microcarpa M. & J. 

 Bull. Torr. Club 49:355 (1922), type loc. North Fork Deep Creek, San Bernardino Mts., John 

 ston 2833. 



Fig. 354. Asclepias ekosa Torr. 

 a, fl. branehlet, X % ; 6, fl., X 1% ; 

 c, hood, X 31/4 ; d, long. sect, of hood, 

 showing the horn, X 3% ; e, foUicle, 

 X %. 



3. A. erosa Torr. Desert Milkweed. (Fig. 354.) Stems 2 to 31/2 feet high; 

 herbage fhiely white-woolly, eventually more or less glabrate; leaves in whorls of 

 2, the blades ovate or ovate-lanceolate, acute or acuminate, 5 to 8V2 inches long, ses- 

 sile; pedicels 1 to li/4 inches long, longer or shorter than the peduncles; flowers 

 very pale cream-color or greenish; hoods when outspread orbicular-obovate with 

 rounded entire or truncatish summit, scarcely exceeding the stamen-column; horns 

 broadly falcate, attached below the middle or at base, esserted from the hood and 

 incurving over the central disk, shaped much like an inverted Lupine keel; follicles 

 oblong-ovate, attenuate at apex, 2V2 to 3^4 inches long. 



