A few members of subgenus Esula sect. Helioscopia

These plants have serrated leaves and glands without appendages. According to Euphorbia PBI, there are about 180 taxa. To go through them all would be very time consuming and well beyond the scope of this project. However, in order to better understand the species that have been introduced to other locations, it is worth discussing a few outside the US that have spread outside of Afroeurasia where most species are native. Notes on leaves refer to the lower leaves and usually includes the similar pleiochasial bracts, but not the dichasial bracts (click here for notes on the bracts). Plants known to occur in New Zealand are marked "NZ" at the end. Plants known to occur in the United States are marked "US" at the end.

E. oblongata - Perennial; stems villous; leaves glabrous, ranging from oblong, elliptic, to broadly lanceolate or ovate, not linear or linear-lanceolate, typically broadest at the base or middle but may be broadest at the apices, apices rounded; glands typically 2-3 (typically 2 in dichasia); fruits warty. Originally from Eurasia, but introduced elsewhere. NZ US
E. depauperata - Perennial; stems glabrous or pilose; leaves glabrous or occasionally pilose, typically linear-lanceolate, sometimes slightly broader, apices typically acute; glands 4-6; fruits warty. Africa.
E. epithymoides - Perennial; stems villous; leaves pilose; broadest towards the middle or base, apices rounded; glands 2-5 (even in same inflorescence) but most commonly 4; fruits covered with many narrow, hair-like warts. Originally from Eurasia, but introduced elsewhere. US
Annuals - Many of these are quite difficult to distinguish and may require seed characteristics.
E. platyphyllos - Annual; stems usually glabrous; leaves glabrous or hairy, usually oblanceolate, typically broadest at apices, apices acute; many dichasia produced before terminal pleiochasium of 3-5 branches; glands 4; fruits warty; seeds smooth, over 2 mm long. Two forms: 1. plants glabrous, more common. 2. plants hairy, less common (specimen 1; photos). Type much more robust than most specimens representing the species. Originally from Eurasia, but introduced elsewhere. NZ US
E. stricta - Annual, glabrous; leaves usually oblanceolate, typically broadest at apices, apices acute; many dichasia produced before terminal pleiochasium of 3-5 branches; glands 4; fruits warty; seeds smooth, under 2 mm long. Two forms: 1. leaves sharply acute, margins sharply serrulate; dichasial bracts mucronate; fruits warts shorter (specimen 1; specimen 2). 2. leaves less sharply acute, margins less sharply serrulate; dichasial bracts mucronate or commonly not; fruit warts long (photos; specimen). Misidentifications? Originally from Eurasia, but introduced elsewhere. NZ
E. spathulata - Annual, glabrous; leaves usually oblanceolate, typically broadest at apices, apices acute; glands 4; fruits warty, warts short; seeds reticulate. Seemingly restricted to North America, widespread. US
E. alta - Annual, glabrous; leaves usually oblanceolate, typically broadest at apices, apices acute; glands 4; fruits warty, warts long; seeds reticulate; restricted to SW United States and NW Mexico. US
E. texana - Annual, glabrous; leaves usually oblanceolate, typically broadest at apices, apices acute; glands 4; fruits smooth; seeds reticulate. Restricted to E Texas and Louisiana in the United States. US
E. helioscopia - Annual, glabrous; leaves usually obovate, broadest at apices, apices rounded or truncate; glands 4; fruits smooth. Originally from Eurasia, but introduced elsewhere. NZ US

Other species:
E. apios: link 1
E. hirsuta: link 1
E. palustris:
E. pterococca: link 1
E. valerianifolia: Fruits sparsely long pilose; link 1

Notes on E. oblongata/depauperata.

Posted by nathantaylor nathantaylor, May 28, 2019 17:41

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