45 6 



EUPHORBIACEAE. 



VOL. II. 



4. CROTONOPSIS Michx. Fl. Bor. Am. 2: 185. 1803. 



Annual slender silvery-scurfy monoecious herbs with branched stems, narrow alternate 

 or rarely opposite short-petioled leaves, the flowers in terminal and lateral clusters. Stami- 

 nate flowers uppermost in the clusters, with an equally 5-parted calyx, 5 petals and 5 inflexed 

 stamens opposite the petals, the filaments distinct, enlarged at the summit. Pistillate flowers 

 with a 3-5-parted calyx, no petals, 5 petal-like glands opposite the calyx-segments, and a 

 i-celled ovary; ovule i; style twice or thrice cleft. Fruit a small scaly or spiny achene-like 

 capsule. Seed lenticular or terete, longitudinally wrinkled; embryo straight in fleshy endo- 

 sperm. [Greek, Croton-like.] 



Two known species, natives of the southeastern United 

 States. Type species : Crotonopsis linearis Michx. 



i. Crotonopsis linearis Michx. Crotonopsis. 



Fig. 2718. 

 C. linearis Michx. Fl. Bor. Am. 2: 186. pi. 46. 1803. 



Silvery, covered with peltate somewhat fringed 

 scales, except on the green upper surfaces of the 

 leaves. Stem wiry, 4'-!* high, much branched; 

 leaves oblong-ovate to linear-lanceolate, -i long, 

 entire ; staminate flowers with an equally 5-parted 

 calyx, the petals spatulate ; calyx of the pistillate 

 flowers unequally 3-5-parted; achene ovoid-elliptic; 

 seed ovoid, l"-li" long. 



In dry sandy soil, Connecticut and New Jersey to 

 Tennessee, Illinois, Missouri, Kansas, south to Florida 

 and Texas. July-Sept. 



5. DITAXIS Vahl ; Juss. Euphorb. 27, 1 10. 

 1824. 



Monoecious herbs or shrubs, perennial by rootstocks, silky or pilose, the sap purplish. 

 Leaves alternate, entire, or rarely toothed, often strongly nerved. Flowers in axillary or 

 axillary and terminal clusters, often racemed, usually bracted. Staminate flowers often 

 crowded at the ends of the racemes; calyx 4-5-lobed, the lobes valvate; petals 4 or 5, alternate 

 with the calyx-lobes and with the lobes of the disk; stamens of the same number as the petals 

 or two or three times as many, united into a column. Pistillate flowers with the calyx-lobes 

 imbricated and smaller petals, the ovary 3-celled, each cavity with i ovule; styles 3, short, 

 once to thrice cleft. Capsule 3-lobed, depressed, separating into 3 2-valved carpels. Seeds 

 subglobose, wrinkled, or muricate, sometimes crested; embryo straight in the fleshy endo- 

 sperm. [Greek, double-ranked, in allusion to the stamens.] 



About 20 species, natives of temperate and tropical regions. Type species : Ditaxis fascicu- 

 late, Vahl. 



Flowers in terminal and axillary racemes; leaves sessile. i- D. mercurialina. 



Flowers in axillary clusters; leaves short-petioled. 2 - D. humilis. 



i. Ditaxis mercurialina (Nutt.) Coult. Tall 

 Ditaxis. Fig. 2719. 



Aphora mercurialina Nutt. Trans. Am. Phil. Soc. (II.) 



5: 174. 1833-37. 

 Argyrothamnia mercurialina Muell. Arg. Linnaea 34: 



148. 1865. 

 Ditaxis mercurialina Coult. Mem. Torr. Club 5: 213. 



1894. 



Stem slender, strict, usually simple, channeled, 

 silky, 4'-2 high. Leaves alternate, ovate to nar- 

 rowly lanceolate, io"-2' long, undulate, sessile, often 

 strongly 3-nerved, glabrate ; flowers in terminal and 

 axillary racemes ; staminate flowers with lanceolate 

 or linear-lanceolate acute ciliate calyx-segments, and 

 spatulate-oblong undulate petals ; pistillate flowers 

 with a 5-parted calyx, the segments lanceolate, spread- 

 ing) 3 times as long as those of the staminate, petals 

 none; capsule depressed, 3"-4J" in diameter, some- 

 what silky, 3-lobed ; seeds globose-ovoid, 2" long, 

 pointed, wrinkled, indistinctly 2-crested. 



In dry soil, Kansas and Arkansas to Texas. Lower 

 leaves sometimes oblanceolate. April-July. 



