FLORA OF THE DISTRICT OF COLUMBIA. 151 



1. ANYCHIA Michx. Forked chickweed. 



Plants finely hairy, rather gtout, the stems with short joints, usually low and spreading; 

 flowers nearly sessile 1. A. polygonoides. 



Plants glabrous, very slender, the stems with long joints, erect; flowers on conspicu- 

 ous pedicels 2. A. canadensis. 



1 . Anychia polygonoides Raf. 



Dry hillsides; frequent. July-Sept. Eastern U. S. (A. dichotoma of some 

 authors, not of Michaux.) 



2. Anychia canadensis (L.) B. S. P. 



Dry woods; frequent. July-Sept. Eastern U. S. (A. dichotoma capillacea Torr.) 



2. PARONYCHIA Adana. 



1. Paronychia dichotoma (L.) Nutt. Whitlow-wort. 



On rocks at Little Falls and Great Falls. July-Oct. Md. to Tex. 



3. SCLERANTHTJS L. 

 1. Scleranthus annuus L. Knawel. 



Easbys Point, north of Old Observatory; Ammendale. May. Native of Eur.; 

 frequently adventive in N. Amer. 



53. ALSINACEAE. Chickweed Family. 



Plants with ' scarioua stipules; leaves sometimes whorled, linear; petals sometimes 

 pink. 



Leaves opposite; petals pink; styles 3 1. TISSA. 



Leaves whorled; petals white; styles 5 2. SPERGTJLA. 



Plants without stipules; leaves never whorled; petals white or wanting. 

 Capsule usually twice as long as the calyx or longer, cylindric, slightly curved, 

 opening at the apex by 10 minute teeth; plants usually with viscid pubescence. 



Petals deeply cleft, or rarely wanting 3. CERASTIUM. 



Capsule less than twice as long as the calyx, ovoid or oblong, not curved, opening 

 by 6 or fewer valves; plants without viscid pubescence. 



Petals deeply 2-cleft 4. ALSINE. 



Petals entire, or sometimes wanting. 



Leaves ovate; sepals acute; styles fewer than the sepals 5. ARENARIA. 



Leaves narrowly linear; sepals obtuse; styles as many as the sepals. 



6. S AGIN A. 



1. TISSA Adans. 



1. Tissa rubra (L.) Britton. Sand spurry. 



Occasional in waste ground and along roadsides. Apr.-July. Widely distributed 



in the U. S.; perhaps native in some parts of X. Amer., but largely adventive from 



Eur. and Asia. (Spergularia rubra Presl; Lepigonum rubrum Fries.) 



2. SPERGTJLA L. 



1. Spergula arvensis L. Spurry. 



Waste ground; Washington and Ammendale. June- July. Native of Eur.; widely 

 naturalized in N. Amer. 



One of our specimens is a very viscid plant with conspicuously margined seeds, 

 suggesting S. saliva Boenn. The seeds, however, are papillose, as in S. arvensis. 

 The differences between the two species do not seem very constant. 



3. CERASTIUM L. 



Petals more than twice as long as the sepals. Plants perennial; pedicels usually 

 lower than the calvx: cansule about twice as long as the sepals. .1. C. velutinum. 



