Xerophyte

Habit

It is a single headed or slowly clumping cactus, usually at or slightly below soil level.

Description

Copiapoa tenuissimaSN|9786]]SN|1138]] is a geophytic cactus arising from a large tuberose root that can slowly branch from the base to form small clumps. It differs from Copiapoa humilisSN|9790]]SN|9790]] for its smaller stems, and its taxonomic status is controversial. It is not clear whether it should be treated as a species or as some lower rank.

Roots

Large tuberose, connected to the stem by long slender neck. The main root may be several times the length of the above-ground body, and serves for storing water. Seedlings naturally produce the huge tap root, starting from germination, i.e. before the plant stem becomes mature.

Flowers

Pretty, yellow diurnal, only 2-2,5 cm long. Tepals up to 15 mm long 5-7 mm wide. Ovary with pubescent scales, floral tube 4-7 mm long. The flowers are supposedly to be sweet scented. (The hairy ovary and fruit are a link with Ritter's PiloSN'>9787' alt='1138'>Copiapoa solaris#SN#9786'>Pilo[[Copiapoa solarisSN' style='border

Blooming Season

Spring and summer. In cultivation in the Copipoa tenuissima are able to flower from immature stems at an early age (c. 2 years from germination) and set viable seed.

Ribs

13-16, developing into tubercles, often spiraling, 3-4 mm tall.

Stem

Flattened to spherical, 2-5 cm in diameter, dull-green, dark olive green, to almost purplish-black, outer skin rough with fine warts. The slightly felted apex can be regarded as a persistent juvenile characters, which can be explained by the need for the plant to multiply as early as possible, before they fall victim to the Guanacos.

Radial Spines

8-14 very thin (almost hairy), acicular, usually straight 3-6 mm long, yellowish to blackish, falling off later.

Fruits

Globose, green to maroon unusual for the genus by being woolly, a primitive characteristic.

Areoles

White abundantly woolly.