Pinus Mature Embryo Labeled – In the Pine Life Cycle

All 18 parts on the diagram

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The seed and its embryo 6

Cotyledons The seed leaves of the embryo. A pine has several.
Hypocotyl The stem of the embryo, below the cotyledons.
Radicle (root tip) The root end of the embryo. It points to the micropyle.
Food store Tissue of the female gametophyte, packed with food for the embryo.
Seed coat The hard outer layer. It forms from the integument of the ovule.
Suspensor A thread of long cells. It pushed the young embryo into the food store.

Cones and pollen 6

Pollen cone The male cone. Its scales carry the pollen sacs.
Pollen sac A case under a scale of the pollen cone. The pollen forms in it.
Pollen grain One grain of pollen. Its two air sacs help the wind carry it.
Seed cone The female cone. Its scales carry the ovules, then the seeds.
Seed scale A scale of the seed cone. It carries two ovules.
Ovule A body that becomes a seed. Two lie on each seed scale.

Inside the ovule 6

Integument The single coat of the ovule. It becomes the seed coat.
Micropyle The opening in the coat. Pollen enters here.
Nucellus The megasporangium. The female gametophyte grows inside it.
Female gametophyte A mass of tissue that bears the archegonia. It later feeds the embryo.
Archegonium The female organ, at the end near the micropyle. It holds one egg.
Pollen tube A tube from the pollen grain. It carries the sperm to the egg.

How this list was compiled: Every name checked on 2026-10-03 and kept only where two of these use it. (1) C. S. Gager, Fundamentals of Botany, 1916, the chapter on the pine (public domain), https://archive.org/details/fundamentalsofbo00gagerich : staminate and carpellate cones on the same tree; on the underside of the microsporophyll the spore-case with the microspores; an air-sac on each side of the pollen grain; the ovuliferous scale with the ovule at its base; the ovule a nucellus (megasporangium) surrounded by an integument that leaves a micropyle; the female gametophyte, later stored as endosperm around the embryo; archegonia at the micropylar end, each with an egg; the pollen-tube; the suspensor; the integument develops into the seed-coat; figure 309 names the hard seed coat, endosperm, embryo, cotyledons, hypocotyl and root-end. (2) E. Strasburger and others, A Text-Book of Botany, second English edition, 1903, the Gymnosperms (public domain), https://archive.org/details/textbookofbotany00stra_1 : pollen-sacs and pollen-grains; the ovuliferous scale of Pinus bearing two ovules; the integument; long tubes push the young embryo deep into the tissue of the prothallium; in an old embryo the radicle, the hypocotyledonary stem and the cotyledons, two or several. (3) J. M. Coulter and C. J. Chamberlain, Morphology of Gymnosperms, 1910 (public domain), https://archive.org/details/b28068105 : in Pinus the suspensor cells elongate enormously, thrusting the embryo into the endosperm; the testa, with its hard layer from the integument. (4) Wikipedia, text only, Pine, Conifer, Cone (botany), Gymnosperm, Ovule and Pollen, https://en.wikipedia.org/wiki/Pine , https://en.wikipedia.org/wiki/Conifer_cone , https://en.wikipedia.org/wiki/Gymnosperm , https://en.wikipedia.org/wiki/Ovule , https://en.wikipedia.org/wiki/Pollen : male (pollen) cones and female cones; microsporangia on microsporophylls; pine pollen has two sacci; a seed scale (ovuliferous scale) with two ovules on its upper side; one integument in gymnosperms; nucellus, micropyle and megagametophyte; archegonia produced by the female gametophyte; a pollen tube carries the sperm to the egg; cotyledons in a whorl on pine seedlings. Licence: own work

The drawing: Drawn for this site on 2026-10-03 from plain geometry; own work, nothing traced. Licence: own work

How it works

A Pinus mature embryo labeled here lies in a ripe seed cut lengthwise, as a microscope slide shows it. The other two drawings go back through the pine life cycle: the cones and pollen, then one ovule.

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The embryo in the seed

The embryo is a young pine: a radicle that points to the micropyle, a hypocotyl, and several cotyledons. Tissue of the female gametophyte is packed around it as a food store, and the seed coat encloses both. The suspensor is the thread that pushed the young embryo into the food store.

From cone to seed

A pine bears pollen cones and seed cones on the same tree. Wind carries the pollen, each grain with two air sacs, to the ovules, which lie two to a seed scale. Inside an ovule the female gametophyte forms archegonia, each with an egg. A pollen tube brings the sperm, and the fertilized egg grows into the embryo.

Older books call the food store of a pine seed endosperm. The quiz takes that, and female gametophyte.
The three drawings are not to one scale: the pollen grain is far smaller than the ovule.

Questions and answers

What are the parts of a mature pine embryo?

A radicle, or root tip, at the end near the micropyle; a hypocotyl, the short stem; and a ring of several cotyledons, the seed leaves. Remains of the suspensor may lie at the root end.

What surrounds the embryo in a pine seed?

A food store, then the seed coat. The food store is tissue of the female gametophyte, which older books call endosperm. The hard seed coat forms from the integument of the ovule.

How many cotyledons does a pine have?

Several, and the number is not fixed. They form a whorl around the tip of the embryo, where a bean has two and a corn kernel has one.

Where are the ovules on a pine?

On the scales of the seed cone. Each seed scale carries two ovules on its upper side, near the base, and each ovule can become a seed.