WOOTON AND STANDLEY— FLOEA OF NEW MEXICO. 413 



87. RHAMNACEAE. Buckthorn Family. 



More or less spiny shrubs 2 meters high or less, with simple leaves and small stipules; 

 flowers perfect or polygamo-dioecious, mostly small and inconspicuous; calyx of 4 or 

 5 valvate sepals, with a disk lining the hypanthium; petals 4 or 5 or wanting; etamens 

 4 or 5, opposite the petals on the throat of the hypanthium or on the disk; pistil of 

 2 or 3 united carpels; ovaries united with the disk and hypanthium to form the 

 beny-like fruit. 



KEY TO THE GENERA. 



Fruit fleshy, black, with a 1 to 3-celled stone. 



Petals present; young stems glaucous 1. Zizyphus (p. 413). 



Petals wanting; young stems not glaucous 2. Condalia (p. 418). 



Fruit dry or somewhat berry-like , 2 or 3-seeded . 



Plants low; petals hooded or long-clawed; stigmas 3 3. Ceanothus (p. 413). 



Tall shi'ubs 1 meter high or more ; petals not clawed nor 



hooded; stigmas 2 4. Rhamnus (p. 414). 



1. ZIZYPHUS Juss. LoTE bush. 



Rigid spiny shrub 1 to 2 meters high, with glaucous young branches and small 

 glaucous leaves, these 15 mm. long or less, ovate to oblong-elliptic, acute or obtuse; 

 flowers small, in axillary corymbs; sepals 5, triangular, keeled within; petals and 

 stamens 5, opposite each other on the disk; ovary 2 or 3-celled; fi'uit a pulpy black 

 berry, green within. 



1. Zizyphus lycioides A. Gray, Bost. Joum. Nat. Hist. 6: 168. 1850. 



Type locality: Between Matamoros and Mapimi, Mexico. 



Range: Western Texas to southern New Mexico and northeastern Mexico. 



New Mexico: Mangas Springs; Berendo Creek; west of Cambray; Florida Moun- 

 tains; Hachita; Dog Spiing; mesa west of Organ Mountains; Organ Mountains. Dry 

 mesas and hills, in the Lower Sonoran Zone. 



2. CONDALIA Cav. 



Very similar to the preceding, but the leaves spatulate and finely pubescent, and 

 the petals wanting. 



1. Condalia spathulata A. Gray, PI. Wright. 1: 32. 1852. 



Type locality: "On the Rio Grande, Texas; and prairies on the San Felipe." 



Range: Western Texas and New Mexico to northeastern Mexico. 



New Mexico: East of Hachita; Las Palomas Hot Springs; mesa near Las Cruces; 

 Guadalupe Mountains. Mesas, in the Lower Sonoran Zone. 



This and the last occur together on the mesas of the southern part of the State. 

 This plant is nearly always leafy, the.leaA'^es being more or less persistent, while 

 Zizyphus lycioides is most frequently without leaves. Much of the time it appears 

 to be merely a bush composed of spines. It may be recognized by its younger 

 branches, which are always bluish green or glaucous, even after the leaves have fallen. 

 The fruits of this and the preceding are sometimes eaten, but their seeds are very large 

 and the amount of pulp small. 



3. CEANOTHUS L. Buckthorn. 



Low shrubs, more or less spiaescent, mostly less than 1 meter high; leaves simple, 

 alternate, with minute caducous stipules; flowers small, in crowded terminal racemes 

 or corymbs; sepals 5, white, petaloid; disk filling the hypanthium; petals 5, white, 

 long-clawed, hooded; stamens t, exserted; ovary immersed in the disk; fruit at last 

 dry, 3-celled, berry-like. 



