EUPHORBIACEAE. 235 



repand-dentate, compressed on the margin ; spines short, thick, divergent, 4—6 

 mm. long. 



Widely established in many places, often forming dense thickets, New I'lvni- 

 dence, Cat Island, Watling's, Long Island and Inagua : — Florida; West Indies; 

 Mexico. Natnralized from India and the Moluccas. Referred by Hitchcock and 

 Mrs. Northrop to Euphoihia antiquoiuiu L. Mottled SruKca;. 



27. AETHROTHAMNUS Kl. & Gke. Monats. Akad. Berlin 1859: 251. 1S.j9. 



Leafless, shrubby f)lauts Avith jointed branches. Involucres not suVjtended 

 by dilated bractlets. Leaves reduced to opposite sessile scales glandular on 

 both surfaces; stipules none. Involucres minutej terminal, campanulate, dioe- 

 cious, minutely bibracteate at the base. Glands transverse, thick, orbicular or 

 semiorbicular, spreading, plane, entire. Bracteoles plumose. Styles 3, bifid, 

 revolute. Seeds ovate-tetragonal, scrobiculate. [Greek, jointed bush.] About 

 10 species, of tropical America and southern Africa. Type species: Euphorbia 

 Tirncalli L. 



1. Arthrothamnus cassythoides (Boiss.) Millsp. Field Mus. Bot. 2: 30G. 1909. 



Eupliorbia cassythoides Boiss. Cent. Euph. 20. 1860. 



Plant 1-2 m. high, the branches white-barked, verticillate below, dichotomous 

 above; branches Avith internodes 8-15 cm. long and 6-7-angle(l, the nodes 

 gummy. Cymes terminal, dichotomous; involucres produced between small 

 thick triangular braotlets ; tube short-campanulate, glabrous within ; lobes 

 triangular-ovate, 4-5-dentatej hairy; glands fleshy; styles short, hairy, bilobate 

 at the apex; capsule ovoid; cocci subcarinate; seeds white, each facet 2-3- 

 foveolate. 



Sandy soil near Deep and Fresh Creeks, Andros : — Cuba. Leafless Ctban 

 Spurge. 



28. TITHYMALUS [Tourn.] Adans. Fam. 2: 355. 1763. 



Annual or perennial milky herbs or shrubby plants with simple or branched 

 stems topped by several-rayed cyme-like umbels. Leaves below the umbel 

 scattered or alternate, estipulate, often broadened upward; bracts of the lunbel 

 quite different from the stem-leaves, entire or toothed. Involucres sessile or 

 peduncled, the lobes often toothed ; glands 4, transversely oblong and appearing 

 reniform by the cornuate extremities or appendages. Capsule Fmooth or 

 tuberculate; cocci rounded or more or less carinate. Seeds variously pitted, 

 often carunculate. [Greek, referring to the milky juice.] About 250 species, 

 of wide geograjDhic distribution. Type species: Euphorbia dcndroidcs L. 



1. Tithymalus trichdtomus (H.B.K.) Kl. & Gke. :\ronats. Aka.l. Berlin 1860: 

 81. 1860. 



Euphorbia tricliotoma H.B.K. Nov. Gen. 2: 60. 1817. 



Perennial, glabrous. Stem commonly branched and more or less woo.ly at 

 the base, the branches erect or ascending, 1-4 dm. tall, widely forking above. 

 Leaves numerous, rather approximate, small, thickish, cuneate to oblong, obtuse 

 or acutish, 5-12 mm. long, minutely erosc when mature; inflorescence trioh- 

 otomous; involucres campanulate, sessile or nearly so, 2 mm. long; glands 

 reniform, 1 mm. long, yellow; capsule tricoccous, the cocci rounded; Feeds 

 white, globose, 2 mm. in diameter, smooth; caruncle thin, circular. 



Coastal sands. Allen's Cay, Great Bahama and Andros : — Florida ; Cul>a : the 

 Cayman Islands. Forking Spurge. 



