Muehlenbeckia astonii,  shrubby tororaro or  shrubby pohuehue is  endemic to the North and South Islands. In the North Island known from Honeycomb Light (Eastern Wairarapa) south to Cape Palliser and just west of Sinclair Head. In the South Island in Marlborough formerly present on the Wairau Bar and Wither Hills, now known only from Clifford Bay, the lower Awatere Catchment to Cape Campbell and Kekerengu. Also in North Canterbury, on Banks Peninsula near Lake Forsyth and on Kaitorete Spit. An old herbarium specimen in Kew suggests it may have once been in the lower Waitaki Valley, South Canterbury.  It grows in coastal to lowland areas. This species is associated with grey scrub communities, largely confined to drier lowland parts of eastern New Zealand. It is found on moderate to high fertility soils. The plant is often found in association with Coprosma crassifolia, Coprosma propinqua (mikimiki), Muehlenbeckia complexa (small-leaved pohuehue), Discaria toumatou,(matagouri), Olearia solandri ,(coastal tree daisy), Ozothamnus leptophyllus (tauhinu) and Rubus squarrosus (leafless lawyer).  It is a deciduous, gynodioecious shrub (having some individual plants bearing female flowers only and others bearing hermaphrodite flowers only) that forms a dense, interwoven masses up to 4 x 4 m. It has numerous slender  branchlets, flexuous, divaricating and interlacing with small almost heart-shaped leaves. It has green or white flowers, on short, axillary fascicles from  August - January (- May), followed by fruit on female plants from  October - June.  Fruit are a small dark three-angled nut with dull faces surrounded by the remnants of the flower which may be either dry and brown, or swollen white and succulent. Its survival in the wild is threatened by lack of regeneration due to competition from exotic grasses, browsing animals and trampling. It is also threatened by loss of its original habitat through disturbance, fragmentation and fire. Many of the shrubby tororaro that survive in the wild are single plants isolated from others of their species. Because male and female flowers occur on separate plants, these specimens have no opportunities to reproduce.