Worm grass Annual herb, small or to more than 1 m tall, nearly glabrous, simple or branched few times, leafless or nearly so except on ultimate segments. Leaves opposite-decussate and petiolate on stems, appearing whorled and usually sessile or nearly so at apex; stipules broadly deltoid, interpetiolar, ca 5 mm long; blades variable but mostly lanceolate-oblong, acute to acuminate, acute at base, 3-18 cm long, 1-6.5 cm wide, scabridulous above and on veins below. Spikes (1) 2-5, terminal, simple or infrequently branched, 3-18 cm long; pedicels obsolete or to 1 mm long; flowers closely aggregated near apex, in all stages and eventually continuous with fruits on basal part of spike; sepals 5, linear-lanceolate, ca 3 mm long, thickened at base, keeled, the margins and keel scabrid; corolla narrowly funnelform, 6-15 mm long, white with a red-violet medial line below each lobe, strongly pleated, the lobes 5, acute, spreading; stamens 5, included; filaments fused to tube in basal half, markedly thickened near point of attachment, the free part arched inward; anthers yellow; style slightly exserted above throat, the apical half swollen, pubescent near apex. Capsules explosive, ca 4 mm long and 6 mm wide, 2-carpellate, sulcate medially, bilobed, compressed at right angles to septum, conspicuously muricate except at base, the persistent base pointed at either end; seeds brown, irregular, to 2 mm long, conspicuously tuberculate, mostly 4-6 per carpel. Croat 7145. Uncommon in weedy areas of the Laboratory Clearing and much less frequent on forest trails; once locally abundant in the vicinity of the old orchidarium north of Kodak House. Flowers throughout the year, principally in the rainy season. The fruits mature quickly. This species contains the toxic, volatile alkaloid spigeline (Blohm, 1962). When the capsule bursts open, the capsule walls become vertically compressed, and the wall and the seeds are usually thrown a distance of more than 1 meter.