Xerophyte

Seeds

Circular to oblong, irregularly angular but not markedly compressed, smooth, thick, 3-5 mm long and wide, pale yellow and lumpy

Description

Opuntia arbusculaSN|10917]]SN|10917]] is a densely branched tree or shrub, up to 3 m high with many intricately branched stems from a solid trunk and thin pencil-like joints 7-10 mm wide, but not infrequently the plant is less than 1 m high and openly branched. It has small flowers that can be dark bronze to pale orange-bronze or green. The fruits are 20-25 mm long, pale green but sometimes tinged with red or purple.

Flowers

Small, dark bronze to orange-bronze, about 2.5-3(-3.5) cm in diameter. Inner tepals moderately spreading, yellow, greenish yellow, or orange-bronze, broadly obovate to spatulate, 17-20 mm, apiculate. The style is white and sometimes light orange distally. The stigma lobes are pale green.

Blooming Season

Late spring (May-June.)

Chromosome Number

C. arbuscula is hexaploid (2n = 66).

Spines

0-3 per areole, of which one longer 8-35(-50) mm long, with often 1 or 2 smaller ones under it, distributed sparsely along segments, stout, usually bent downward, light to dark grey or yellow ir reddish brown near base, ageing black with age. Each spine is clothed by a loose fitting, l yellowish or yellowish brown sheath.

Stem

Main stem (trunk) well developed 10-12 cm in diameter. The ultimate segments are cylindrical, smooth, green with purple tint, 6-11 cm by 5 to 30 mm in diameter, with narrow, obscure tubercles about 1-2 cm long appearing as wrinkles when dry.

Fruits

Commonly sterile, bovoid, truncate and deeply excavated at summit, fleshy, mostly spineless, green to yellow, sometimes tinged red to purplish at areoles, fertile ones stipitate, obconic, 2.5-3(-5) cm long, 1.5-3.5 cm in diameter, sometimes proliferous. Areoles 15-17(-34). Umbilicus 3-4 mm deep.

Areoles

Broadly elliptic to round, 1-2 mm in diameter, 4-55 mm apart with tan to brown wool. Glochids pale yellow encircling areole. Usually only a few areoles spiniferous.