Phyllanthus polygonoides Spreng., knotweed leaf–flower. Perennial herb (± suffrutescent), winter–deciduous, taprooted, not rosetted, many–stemmed at base, clump–forming from woody stems just above the ground, ascending, in range 10—30(—50) cm tall; ± monoecious (occasionally plants are only staminate or pistillate); shoots with only cauline leaves on slender stems, leaves ascending and loosely appressed, so leaves ± overlapping, glabrous, foliage somewhat glaucous (especially lower surface of blades); sap somewhat milky, not copious.
Stems of young shoots cylindric, < 1 mm diameter, later with projecting old leaf bases flanked by persistent, dried pairs of stipules; aboveground woody stems ca. 1.5 mm diameter, bark purplish; belowground stems < 4 mm diameter.
Leaves helically alternate, simple, petiolate, with stipules; stipules 2, attached on projecting leaf base at base of petiole, each suberect to appressed, acuminate with a clasping basal lobe, 1—2 mm long, white drying purplish red and light brown, clasping lobe rounded on outer margin; petiole cylindric, < 1 mm long, yellowish green, with a constriction around base (abscission zone); blade oblanceolate to oblong, 1.5—11 × 2—3 mm, ± rounded to obtuse at base, entire, acute with short point at tip, pinnately veined with midrib raised slightly on lower surface, lower surface lighter in color (bi–colored).
Inflorescence cyme, axillary, of (0)1 pistilate flower and (0)1—4 smaller staminate flowers, glabrous; bractlet subtending pedicel lanceolate to narrowly lanceolate, < 0.5 mm long, white; pedicel at anthesis 2—2.5 mm long, of pistillate flower thicker and increasing in length and curved in fruit.
Staminate flower radial, ca. 2 mm across; perianth (calyx) 6–lobed, yellow–green; tube cup–shaped, ± 0.25 mm long; lobes scarcely overlapped at base, ascending to spreading, ± elliptic, 1—1.3 × 0.5—0.7 mm, central green portion raised and with narrow white margins, lobes scarcely overlapped at base; nectaries 6, in whorl outside stamens, ± circular to oval and pouchlike, ca. 0.3 mm, yellow, nectar–producing; stamens 3, fused into columnar, 0.6—0.7 mm long, greenish, 3–branched above midpoint; anthers dorsifixed, dithecal, 0.4 mm long, yellow, longitudinally dehiscent; pollen yellow; pistil absent
Pistillate flower radial, ca, 3 mm across; perianth (calyx) 6–lobed, yellow–green; tube cup–shaped, ± 0.4 mm long; lobes scarcely overlapped at base, ascending to spreading, ovate, 1.5—1.8 × 1 mm increasing 2× and tightly appressed in fruit, central green portion raised and with narrow white margins, lobes strongly overlapped at base; nectaries 6, in whorl, ± circular to oval and pouchlike, ca. 0.3 mm, yellow, nectar–producing; stamens absent; pistil 1; ovary superior, oblate, 6–lobed, at anthesis 0.7 × 0.9 mm, green, 3 grooves deeper, glabrous, 3–chambered, each chamber with 2 ovules; style in slight depression at top, 3–forked with stout base, branches spreading, 0.35—0.4 mm long, greenish; stigmas 2, divergent at tip of branches, short
Fruit capsule, schizocarpic splitting from base upward into units, 6–lobed (grooves not pronounced), 3–chambered, ca. 1.8 × 3 mm, valves with purplish venation before drying, with persistent style in depression at top; perianth lobes tightly appressed to capsule, with purplish, pinnate venation
Seed wedge–shaped, 3–sided, and D–shaped, 1.2 mm long, dark brown, sides flat and back rounded with elaborate surface texture; hilum linear along narrow (inner) edge.
A. C. Gibson