Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.
......4 Plants either annual or perennial from slender wintering stems; leaves flexuous, lacking axillary fascicles; stem and inflorescence variously stipitate-glandular to glabrous, sepal nerves 3 or 5.
........5 Sepal nerves 3 (occasionally weakly 5), widely spaced, not appearing ribbed; inflorescences divaricately-branching at maturity, forming a diffuse tangled mound in robust specimens; seeds 0.8-0.9 mm across; flowering time centered May through June
........5 Sepal nerves 5, typically closely spaced and appearing elevated and ribbed (widely spaced in some specimens); inflorescences ascending to spreading at maturity; seeds 0.5-0.7 (-0.75) mm across; flowering time centered April through May