5(4). Sepals more or less entire; petals ovate to elliptic; flowers of those 

 racemes that occur on green branches with 1 or 2 of the filaments 

 inserted between lobes of disk 3. T. chinensis. 



5. Sepals denticulate; petals obovate; all filaments of all flowers inserted below 

 disk near margins 6. T. ramosissima. 



1. Tamarix africana Poir. 



Bark black to dark-purple; leaves sessile; racemes 3-7 cm. long, 6-9 mm. broad 

 (in dry material), those occurring on green branches of the current year somewhat 

 smaller; bracts longer than pedicels; flowers pentamerous; sepals subentire, the 

 outer 2 slightly keeled and longer than the inner more obtuse ones; petals ovate to 

 broadly trulliform-ovate, about 2.5-3 mm. long in vernal flowers, 3 mm. long or 

 more in aestival; staminal filaments inserted on gradually tapering lobes of disk. 



Nat. of Eur. and the Medit. region; introd. in Cailf., Ariz., Tex. and S.C. 



2. Tamarix aphylla (L.) Karst. 



Bark reddish-brown to gray; leaves vaginate; racemes 3-6 cm. long, 4-5 mm. 

 broad; bracts longer than pedicels; flowers pentamerous; sepals entire, the inner 

 somewhat larger; petals elliptic-oblong to ovate-elliptic, 2-2.25 mm. long, caducous, 

 sometimes 1 or 2 persisting after maturity; staminal filaments inserted between 

 the more or less retuse disk-lobes. 



Nat. of Afr. and the Middle East; introd. in Tex., Ariz, and Calif. 



3. Tamarix chinensis Lour. Fig. 536. 



Bark brown to black-purple; leaves sessile; vernal inflorescences of many dense 

 racemes, aestival ones loose and of slender racemes; racemes 2-6 cm. long, 5-7 

 mm. broad; bracts equaling to slightly longer than pedicels; flowers pentamerous; 

 sepals subentire, acute; petals elliptic to ovate, persistent after maturity, about 

 1.5-2.25 mm. long; filaments inserted between lobes of disk but from its lower 

 part near the margin; in aestival flowers 1 or 2 filaments are inserted in the sinuses 

 between the lobes and the other 3 or 4 under the disk near the margin. 



Nat. of the Far East; introd. and widespread in Can. and the U.S. 



In regard to the insertion of the filaments either direct from the disk surface or 

 from the lower surface near its margin, the separation of this species and the poorly 

 known (not included here) T. aralensis Bunge is most tenuous. 



4. Tamarix gallica L. Tamarisco, rompevientos. 



Bark blackish-brown to deep-purple; leaves sessile; racemes 2-5 cm. long, 4-5 

 mm. broad; bracts longer than pedicels, not exceeding the calyx; flowers penta- 

 merous; sepals acute, entire or subentire; petals caducous, elliptic to slightly ovate- 

 elliptic, 1.5-1.75 mm. long; staminal filaments inserted on apices of the gradually 

 attenuating lobes of disk. 



Nat. of s. Eur.; introd. and rare in s. U.S. 



Tamarix canariensis Willd., a species allied to T. gallica, is known to have been 

 introduced recently into Arizona. It has densely incised-denticulate sepals and the 

 rachis of the raceme is papillose. 



5. Tamarix parviflora DC. 



Bark brown to deep-purple; leaves sessile; racemes more often on last year's 

 branches, 1.5-4 cm. long, 3-5 mm. broad; bracts diaphanous, longer than pedicels; 

 flowers tetramerous; sepals eroded-denticulate, the outer 2 trulliform-ovate. acute 

 and keeled, the inner 2 ovate and obtuse; petals parabolic or ovate, 2 mm. long; 

 staminal filaments emerging gradually from the disk-lobes. 



Nat. of the Medit. region; introd. and widespread in Can. and the U.S. 



1149 



