Description Pinus monophylla

1 description

1.1 species
1.2 subspecies , genetics

1.2.1 mojave national preserve

description

pinus monophylla, closeup of single needle in each sheath


species

pinyon pine 2-year cone cycle

pinus monophylla small medium size tree, reaching 10–20 m (33–66 ft) tall , trunk diameter of 80 cm (31 ⁄2 in) more. bark irregularly furrowed , scaly. leaves ( needles ) are, uniquely pine, single (not 2 or more in fascicle, though trees needles in pairs found occasionally), stout, 4–6 cm (1 ⁄2–2 ⁄4 in) long, , grey-green glaucous blue-green, stomata on whole needle surface (and on both inner , outer surfaces of paired needles). cones acute-globose, largest of true pinyons, 4.5–8 cm (1 ⁄4–3 ⁄8 in) long , broad when closed, green @ first, ripening yellow-buff when 18–20 months old, small number of thick scales, typically 8-20 fertile scales. cones grow on two-year (26-month) cycle, newer green , older, seed-bearing or open brown cones on tree @ same time (see image @ left).

open cone empty pine nuts

the cones open 6–9 cm (2 ⁄4–3 ⁄2 in) broad when mature, holding seeds on scales after opening. seeds 11–16 mm (⁄16–⁄8 in) long, thin shell, white endosperm, , vestigial 1–2 mm (⁄32–⁄32 in) wing. empty pine nuts undeveloped seeds (self-pollinated) light tan color, while ones dark brown. pine nuts dispersed pinyon jay, plucks seeds out of open cones, choosing dark ones , leaving light ones (as in image @ right). jay, uses seeds food resource, stores many of seeds later use burying them. of these stored seeds not used , able grow new trees. indeed, pinyon seeds germinate in wild unless cached jays or other animals.

subspecies , genetics

there 3 subspecies:

pinus monophylla subsp. monophylla. of range, except areas below. needles more stout, bright blue-green, 2-7 resin canals , 8-16 stomatal lines. cones 5.5–8 cm (2 ⁄8–3 ⁄8 in) long, longer broad.


mature pinus monophylla subsp. monophylla in snow, mono co. california



pinus monophylla subsp. californiarum (d. k. bailey) zavarin. southernmost nevada, southwest through southeastern california (northwest far san jacinto mountains) 29°n in northern baja california. needles less stout, gray-green, 8-16 resin canals , 13-18 stomatal lines. cones 4.5–6 cm (1 ⁄4–2 ⁄8 in) long, broader long.
pinus monophylla subsp. fallax (e. l. little) d.k. bailey. slopes of lower colorado river valley , adjacent tributaries st. george, utah hualapai mountains, , along lower flank of mogollon rim silver city, new mexico. needles less stout, gray-green, 2-3 resin canals , 8-16 stomatal lines. cones 4.5–6 cm (1 ⁄4–2 ⁄8 in) long, broader long.

it closely related colorado pinyon, hybridises (both subsps. monophylla , fallax) ranges meet in western arizona , utah. (subsp. californiarum) hybridises extensively parry pinyon. classification of pinyon species based upon presence of single-needle fascicles brought doubt reporting of trees both pinus monophylla/pinus edulis , pinus monophylla subsp. fallax/pinus edulis zones growing more single needle fascicles after dry years , more two-needled fascicles after wet years.

mojave national preserve

an isolated population of single-leaf pinyon trees in mojave desert s new york mountains, within mojave national preserve of southeast california, has needles in pairs , thought colorado pinyons. have been shown two-needled variant of single-leaf pinyon chemical , genetic evidence.

occasional two-needled pinyons in northern baja california hybrids between single-leaf pinyon , parry pinyon.