EcHiNocrsTis. CUCURBITACE^. 251 



Mohawk. Fl. July - August. Fr. September. An ornamental plant when in full flower, 

 being covered with numerous graceful racemes of whitish flowers. It is sometimes seen in 

 gardens. 



The name Hexameria, given to this genus in my Report of 1840, was changed, because it 

 had been employed previously by Bennett in his Plant. Jav. rariores. 



Group 16. Ovaries 2 or more, many-ovuled, distinct or more or less united. Calyx 

 free from the ovary, or the tube partly (rarely wholly) united to the ovary. 

 Petals and stamens (mostly definite) inserted on the calyx. Seeds numerous, 

 albuminous. 



Order XLV. CRASSULACEtE. Juss. The Houseleek Tribe. 



Sepals 4 - 5 (in Sempervivum 6 - 20), free from the ovaries, persistent, more or 

 less united at the base. Petals as many as the sepals, sometimes combined 

 into a monopetalous corolla. Stamens as many or twice as many as the petals. 

 Pistils always equal in number to the sepals, distinct or partly united. Carpels 

 follicular, usually several-seeded. — Herbaceous or sometimes suffruticose 

 plants, mostly fleshy or succulent, with simple leaves and the flowers commonly 

 in cymes or racemes. 



1, TILLiEA. Mich. gen. t. 20; Endl. gen. 4607. TILLJEA. 



[ In honor of Mich. Atjg. Tilli, an Italian botanist who died in 1740.] 



Sepals, petals and stamens 3-4. Carpels 3-4, distinct, opening by the inner suture, 

 2 - many-seeded. — Small, more or less aquatic plants, and small axillary flowers. 



* BuLLiiRDA, DC. Flowers tetramercnts : petals oval or oblong: hypogyrums scales linear: carpels 5 - 20-seeded. 



1. TiLL^A SIMPLEX, Nutt. Pigmy-wced. 



Stem difi"usely branching from the base, and rooting ; the branches ascending ; leaves 

 linear-oblong, rather obtuse, connate at the base ; flowers solitary, nearly sessile ; petals nearly 

 as long as the carpels, and twice as long as the sepals. — Nutt. in jour. acad. Phil. I. p. 114, 

 and gen. appx. ; DC. prodr. 3. p. 381 ; Torr. ^ Gr. fl. N. Am. 1. p. bSl. T. ascendens. 

 Eat, man. ed. 8. p. 453. 



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