Opuntia bentonii

Opuntia bentonii View in CoL

Opuntia anahuacensis

Shrub to 1.5–2 m across and 1.5 m tall Low spreading to 0.5(1) m tall and 2–3 m across

Plants taller,shrub-like,not low spreading Plants shorter,horizontally spreading,sometimes prostrate Cladodes wider,mostly ± 18 cm wide and ± 27 cm long Cladodes narrower,mostly ±13 wide and 22–27 cm long Cladodes broadly obovate,oval,or subcircular,never narrow. Cladodes obovate,rarely broadly obovate,manifestly tapering to Cladodes not noticeably tapering to the base,never forming the base sometimes forming a neck

a neck

Areoles 3–4 in a diagonal line on cladode surface Areoles 4–5 in a diagonal line on cladode surface

Areoles slightly raised when new Areoles always flat

Vasculature between areoles may be visible and somewhat Vasculature not elevated

elevated as raised lines on new cladodes

Glochids yellow or golden brown,not in an adaxial tuft Glochids initially brownish-yellow in an adaxial tuft

Glochids in areoles on face of pads longest in semicircle or cluster Glochids in areoles on face of pads initially in small,tight,fairly near upper edge of areole with some scattered throughout the even tuft above center of areole,becoming scattered sparsely areole from the beginning throughout the areole only uncommonly after several years Zero to 2(3) spines,erect,semi-erect,or one occasionally deflexed, Zero to 2 spines,sometimes one reflexed,plants sometimes plants appearing moderately spiny appearing essentially spineless

Flowers 9–10 cm across Flowers to 8–9 cm across

Flowers all yellow Flowers all yellow or red and yellow

Filaments yellow If flowers red and yellow,filaments may be tinted pink

Style greenish-white at anthesis Style white at anthesis

Cylindrical style Bulbous style

Stigma pale yellow to pale yellowish-green Stigma white

Pericarpel not elongate,± 3 cm Pericarpel elongate, 4–6 cm

Fruit egg-shaped or short pyriform Fruit pyriform to clavate

Seeds modestly reniform,margin thickish Seeds subcircular,margin thin

Seeds overall flat and thin Seeds thickish

Flowering in O. bentonii was observed from late April to early July. The greatest bloom was in late May to early June, and a few flowers were noted in early fall. Ripe fruit was observed beginning in July. Multiple cladodes at the Texas Point National Wildlife Refuge bore ripe fruits adjacent to aborted fruits. Aborted fruits also occurred on plants at Seadrift, Texas. However, the aborted fruits were of different shapes and colors at the two locations ( Fig. 3 View FIG ; Fig. 6 View FIG ). Possibly the fruit failures were due to lack of pollination or larval insect damage to developing ovaries as reported for other Opuntias ( Miller et al. 2009; Piña et al. 2010). Overt evidence of herbivory was not observed though some fruits showed damage indicative of small mammal or bird frugivory.

Opuntia bentonii View in CoL was reported to be a possible component of the pest-pear invasion of Australia that devastated millions of square kilometers of agricultural land in the late Nineteenth and early Twentieth centuries ( Alexander 1927). However, it is unclear if the references are actually to O. bentonii View in CoL , O. anahuacensis View in CoL , O. stricta View in CoL , or some other species because the identification of Opuntia View in CoL was imprecise at that time in Australia ( Johnston & Tryon 1914). Therefore, the potential of O. bentonii View in CoL as a weedy species is unknown. However, viable pieces of O. bentonii View in CoL have been observed floating in the ocean surf and at least temporarily rooting among washed-up debris from Biloxi, Mississippi to Galveston, Texas. Thus, O. bentonii View in CoL may be dispersed by maritime means as has been proposed for other Opuntias ( Majure et al. 2007).