172 Proceedings of the Biological Society of Washington. 



slender rootstocks. This character is sometimes shown in her- 

 barium material, but too often the dried specimens show nothing 

 of the underground parts. Iresine celosioides is typically an 

 annual, with a slender or stout taproot. Under favorable tropi- 

 cal conditions the plants doubtless persist for more than a 

 single season, but they never, so far as known, develop root- 

 stocks. Nor is this important difference in habit the only 

 character which differentiates the two species. In Iresine celosi- 

 oides the sepals of the pistillate flowers are 3-nerved, usually 

 obtuse, and longer than the utricle, while in the species here 

 described they are faintly 1 -nerved, acute, and equal to or 

 usually shorter than the utricle. In herbarium material there 

 is an evident difference in general appearance, the leaves of the 

 former being usually yellowish, small, and thick, while those 

 of the latter are bright green, larger, and thin. 



Iresine rhizomatosa Standley sp. nov. 



Iresine celosioides Michx. Fl. Bor. Amer. 2: 244. 1803, and of many 

 other authors ; not Iresine celosioides L. 



Iresine paniculata Uhne & Bray, Bot. Gaz. 21 : 353. 1896, in part, and 

 of recent American authors ; not Celosia paniculata L. 



Perennial from slender elongate horizontal rootstocks; stems commonly 

 solitary, herbaceous, stout or slender, erect, 3-15 cm. high, usually 

 simple up to the inflorescence, sparsely villous with short hairs, more 

 densely villous at the nodes, sometimes glabrous throughout, the nodes 

 slightly swollen, the internodes 5-14 cm. long; petioles slender, 0.8-3 cm. 

 long; leaf blades broadly deltoid-ovate to ovate or elliptic-oval, 6-15 cm. 

 long, 2-7 cm. wide, acute or rather abruptly acute to long-acuminate at 

 the apex (or the lowermost very rarely obtuse), truncate to acute at the 

 base and usually slightly decurrent, thin, bright green, bearing a few 

 scattered short stout hairs on the upper surface along the veins, sparsely 

 pubescent beneath with short stout soft hairs, or sometimes nearly 

 glabrous; pistillate panicles 7-30 cm. long and 2.5-20 cm. broad, much 

 branched, the stoutish branches erect or ascending, usually deiase, 

 sparsely villous, the spikelets alternate or opposite, stout, densely 

 flowered, 0.5-2 cm. long, the staminate panicles often laxly branched 

 and with longer spikelets ; bracts white, equaling or somewhat shorter 

 than the sepals, ovate to ovate-orbicular, acute or acutish ; sepals ovate- 

 oblong or oblong, acute or acuminate, 1-1.3 mm. long, faintly 1-nerved, 

 white, the pistillate flowers bearing copious long white wool at the base; 

 lobes of the staminal cup nearly obsolete ; utricle equaling or commonly 

 longer than the sepals; seed suborbicular, dark red, shining, 0.5 mm. in 

 diameter. 



Type in the U. S. National Herbarium, No. 865,290, collected in shaded 



