What plant is that?

Click on photo below to view larger image
False Aster plant
False Aster flowers

False Aster close upFalse Aster seed head
Upper left and lower photos:© Francis R. Underwood 2019
Upper right©David G. Smith, http://www.delawarewildflowers.org

This month’s mystery plant is not native to New England, but it does occur in Rhode Island and Massachusetts.  In Rhode Island I  have seen it growing in Warwick and Providence.  It is a plant which grows in wet places such as along pond shores and in alluvial habitats.  This plant is an annual composite with ray flowers growing around the outside of the flower head which are white while the flowers in the center of the head are tubular (discoid). The ray flowers are very short and only 3-4mm long.  The plant sometimes sprawls and roots at the nodes in very wet habitats but along pond shores it is more upright in growth up to 5-12” or more in height  The leaves are pinnately veined, opposite, 2-8 cm in length, lance-shaped, short  petioled or sessile, and rather narrow.  This plant grows 2-10” in height.  This plant is not included in Newcomb’s Wildflower Guide. The GoBotany site online is perhaps a better guide to an accurate identification.  Note in the third sentence above that the word composite is sometimes used to refer to the aster family.

It’s. . .

Botanical Name:
Eclipta prostrata, Yerba-de-tago
Common Name:
  False Aster, Yerba-de-tago
  Asteraceae ( Aster Family)
  Alluvilial areas and pond shores