474 ASCLEPIADACE.E. Cydadenla. 



ovate, several-ribberl from or near the base and witli a stronger midrib, the base 

 contracted into a conspicuous margined petiole : peduncles terminal, becoming 

 lateral, scape-like, cymosely or corymbosely few-llowered ; the bracts alternate : 

 pedicels filiform, much twisted after flowering : corolla rose-color or purple. — PI. 

 Hartw. 322, & Gen. PL ii. 728. 



1. C. humilis, Benth. 1. c. Glabrous throughout and green, or with minute 

 hoariness when young : leaves ovate or sometimes obovate, thickish, 1 to 3 inches 

 long. 



"Mountains of tlie Sacramento" {Hartireg), of Shasta Co. {Brciccr), and of Plumas Co., Lcin- 

 mon, &c. Corolla three fourths and the lobes one fourth of an inch in length, inserted on a thin 

 tliit disk at the bottom of the calyx, suiTounding the nearly entire saucer-shaped nectary which 

 characterizes the genus. 



2. C. tomentosa, Ch-ay. Tomentose-hirsute throughout : leaves ovate and ob- 

 long-ovate (2 or 3 inches long, besides the petiole) : calyx hirsute. 



Plumas Co., between Big Meadows and Indian Valley, with the preceduig (of which it may he 

 only a variety), Lcrmtion. 



Order LXI. ASCLEPIADACE.^. 



Herbs (as to temperate regions), with milky juice, no stipules, and regular flowers 



with the parts in five, except that there are two carpels with distinct ovaries, Ijut a 



common stigma ; the stamens surrounding and attached to this ; the pollen in solid 



masses, in ours all the pollen of each anther-cell in one waxy mass. Leaves entire, 



generally opposite, sometimes whorled, rarely alternate. Calyx and corolla in ours 



almost valvate. Flowers usually in simple umbels. Fruit a pair of follicles. Seeds 



almost always with a coma of silky down. 



A large order, nearly related only to the preceding, from which the peculiarities of the 

 stamens, mentioned above, readily distinguish it, widely distributed oA^er the temperate and 

 warmer parts of the world, hiit very scanty in Europe, and feebly represented on the Pacific side 

 of North America. The sensible properties nearly those of Apocynacecv, the juice more or less 

 acrid and containing caoutchouc, and the inner bark (especially in Asclcjna^s) abounding with 

 very tough bast-fibre. 



* Erect herbs : a hooded appendage (nectary) beliind each anther. 



1. Asclepias. An incurved horn or projecting crest from the cavity of each hooded appendage. 



2. Gomphocarpus. No horn to the appendages. 



* * Twining herbs. 



3. Sarcostemma. Crown a ring in the throat of tlie rotate corolla : pollen-masses vertical. 



4. Lachnostoma. Crown as in Axlcj)ias : pollen-masses horizontal. See Ajrpendix. 



1. ASCLEFIAS, Linn. Milkweed. Silkweed. 



Calyx and corolla both deeply 5-parted ; the divisions small and reflexed. Fila- 

 ments inserted on the very base of the corolla, monadelphous, short, often very 

 short, crowned behind each anther with a conspicuous hood-like appendage, from 

 the cavity of which rises a subulate and usually felcate horn : anthers conniviug 

 around and adherent to the solid stigma, their thin and broad scarious tips inflexed 

 over its truncate summit, the wing-like cartilaginous edges meeting and more or 

 less projecting between tlie hoods : wax-like pollen-mass of each cell pear-shaped, 

 tapering above into a stalk by which it is suspended, along with a pollen-mass from 

 an adjacent anther, to a black gland aflixed to the upper edge of the stigma alter- 



