Xerophyte

Leaves

The opuntias, like most of the cacti, lack proper leaves (they are reduced in this plant to small green conical-cylinder, which then fall away early).

Seeds

4 mm broad (weight 0.016±0.001 g )

Description

Opuntia tomentosaSN|34821]]SN|34821]] is shrubby or tree-like species becoming 3 to 6 meters high,but occasionally reaching up to 8 m in height. It has a broad top a smooth trunk and dull green segments (often incorrectly called leaves) which are velvety to touch due to the dense covering of short fine hairs. The flowers are a deep orange. This species was first described from cultivated plants and has long been a favorite. When grown out of doors it forms a large and conspicuous plant. It is usually nearly or quite spineless, but plants which come from the Valley of Mexico are often spiny.

Note

The denomination "tomentosa" indicates that this species, instead of spines (it often lacks them, especially in larger plants and in the stem, or has them thin and of small size), but has "tomento", very fine hairs on it.

Flowers

Yellowish, orange or red, 4 to 5.5 cm long; Outer segments often with reddish markings. Filaments white or rose-coloured; style dark carmine, longer than the stamens; stigma-lobes 5 or 6, white. Flowers usually arise singly on fleshy bases along the margins of the stem segments or sometimes in the flat part of the younger segments. Flowering occurs mostly during the warmer time of the year in spring and summer.

Spines

0-4. Young plants have 2–4 white or pale yellow spines, 0.5-1.5 cm long, located in the areoles with one spine reaching a length of 2.5 cm. The areoles usually become spineless as the plant matures. Spines are needle-like to weakly awl-like, straight, whitish yellow, and become grey with age. A more spiny variety does exist and has more than 50 spines in each areole on the trunk.

Stem

Main central stem (trunk) woody, 0.7-5 m high and 10 to 30(-40) cm in diameter at its base. Branches divided into oblong to narrowly obovate segments (joints or cladodes) similar to leaves. Segments (10-)15-30(-35) cm long, (6-)8-12(-16) cm wide and 1.5–2 cm thick, fleshy (i.e. succulent) velvety pubescent, green to dark green, shiny, somewhat tuberculate when young. The lower ones becomes lignified with time to form the trunk and branches.

Fruits

Ovoid, obovoid or globose with their apex depressed (saucer-shaped) with circular lines that meet in the centre and give the fruit a shrivelled appearance, pubescent, spineless, but protected with glochids, 3.5-5.2 cm long, 2.5-4 cm in diameter. At first they are green, then they mature and turn dull purplish-red; they are fleshy, sweetish and edible. Each fruit contain on average 80 (±9) seeds within a reddish pulp.

Areoles

The areolas (small protuberances in the stem) are in this species slightly rised (especially in periods of water stress), and are provided with light yellow glochids 1-5 mm long.