Xerophyte

Seeds

Black, warty, 0,9-1,1 mm long, 0,8-0,9 mm wide.

Description

Echinocereus viridiflorus var. davisii is the tiniest Echinocereus species, and one of the smallest cacti in the world, plants are extremely diminutive and mostly subterranean (geophytes), usually do not offset. The diminutive size and the reduced number of ribs (6-10) distinguish E. viridiflorus v. davisii from all other species of the Echinocereus viridiflorusSN|11085]]SN|11071]] complex. Moreover it has no wool on the ovary areoles while the other does.

Roots

Fibrous in young plant became tuberous in age.

Flowers

Funnel-shaped, campanulate or occasionally rotate, usually not opening widely, yellow-green or straw-yellow, weakly lemon-scented 1,5-2,5 cm long, 1,5-2,7 cm across, often larger than stems, (buds acute, reddish and yellow-greenish). Ovary and floral tube slender with 10-14 areoles bearing short plumose spines and not woolly. Inner perianth segments straw-yellow or greenish-yellow, linear to slightly broadened above, pointed, bluntly rounded or emarginate. Outer perianth segments narrow, pointed and entire, with midlines reddish or umber and the margins yellow. Stile pale green up to 1,4 cm long, exerted above the anther, with 5-7 green heavy stigma lobes. Filaments pale green 5-9 mm long, pollen light yellow. They are self-incompatible.

Chromosome Number

2n = 22

Spines

Partially or mostly obscuring the stem, needle-like, usually all radial, but mature specimens may occasionally produce a single reddish-purple central spine 1-1,2 mm long.

Ribs

6-10 divided in prominently raised tubercles 2-2,5 mm tall.

Stem

Spherical to ovoid or top-shaped, with a large underground portion merging with the swollen rootstock, dark green epidermis up to 1-2(-3,5) cm in high and 0,8-2,5(-3) cm in diameter, but cultivated specimens can grow bigger (up to 8 cm tall and 6 cm in diameter) and stems eventually branch into compact clumps. E. viridiflorus var. davisii are not short lived, but when they reach the mature flowering size, they continue to produce new areoles and bloom for decades, but hardly increase in size.

Fruits

Green with reddish tinge or purplish-brown, dry, oval, 5-11 mm long, 4-5(-8) mm in diameter. At maturity the fruit splits open vertically and soon dry out. The spiny areoles are deciduous. Each usually seed contains less than 40 seeds.

Habit

Usually solitary, but branched plants are found occasionally.

Blooming Season

Blossoming and fruiting occur on 3 to 4 year-old plants. Blooming period in cultivation is March-April and the flowering period usually lasts 10-20 days (but this period must be expanded under favorable growing conditions. The flowers open in the morning till afternoon and again for 3-4 days after closing at night.

Radial Spines

8-14 more or less pectinate, white with the outer one-half of a contrasting black or reddish-purple colour, turning to grey or white with reddish or dark brown tips, upper ones slender, round, 4-7 mm long, lateral ones stouter, usually flattened, 11-19 mm long, straight or somewhat curved or recurved against stem. Young seedling have tiny, feathery, pectinated spines which are flattened against the stem and white.

Areoles

Narrow oval to elongated 3-4,5 mm long, with scarce wool, even when young.