heartwood [
PO:0004512; plant anatomy term ]
A portion of secondary xylem (PO:0005848) that lacks living secondary xylem parenchyma cells (PO:0004525).
More Synonyms: duramen (Spanish), 心材 (Japanese)
Comments: Heartwood has ceased to function in storage and conduction, and the reserve materials have been removed or converted into heartwood substances. It is generally darker colored than sapwood (PO:0004513) and is found in the center of a shoot axis (PO:0025029) or root (PO:0009005), interior to the sapwood. Heartwood forms at the end of a cell death stage of secondary xylem (PO:0025466).
helobial endosperm [
PO:0006017; plant anatomy term ]
An endosperm in which the first karyokinetic event is accompanied by the formation of a horizontal wall which divides the central cell into unequal regions. The larger one is the micropylar chamber in which cytokinesis does not occur and the smaller one is the chalazal chamber.
More Synonyms: endosperma helobial (Spanish), 沼生目型胚乳 (Japanese)
Comments:
higher order leaf vein [
PO:0008023; plant anatomy term ]
A leaf lamina vein (PO:0020138) arising from a quaternary (PO:0008022) or other higher order leaf vein.
More Synonyms: cross-vein, 高次葉脈 (Japanese), fifth and higher order leaf vein, veinlet, vena de alto orden (Spanish)
Comments: Vein orders only apply to hierarchically branching vein patterns, not to dichotomously branching vein patterns, as found in some ferns and gymnosperms.
hilum [
PO:0020063; plant anatomy term ]
A cardinal part of multi-tissue plant structure (PO:0025498) that is a scar on a seed (PO:0009010) at the place where it was attached to a funicle (PO:0020006).
More Synonyms: hila, hilo (Spanish), 核(デンプン粒)、へそ(種子) (Japanese)
Comments:
hilum groove [
PO:0004719; plant anatomy term ]
A canal (PO:0025132) that is a longitudinal groove in the testa through a prominent hilum (PO:0020063) of a seed (PO:0009010).
More Synonyms: へそ(種子)溝 (Japanese), faboid split, surco del hilium (Spanish)
Comments:
hydathode [
PO:0005660; plant anatomy term ]
A cardinal organ part that releases water through a hydathode pore.
More Synonyms: hidatodo (Spanish), 排水組織 (Japanese)
Comments: Hydathodes may have one or more pores that are similar to stomata but lack the ability to open and close. Hydathodes are involved in the release of water or xylem sap through pores via guttation or secretion. Generally, hydathodes are located at the end of a minor vein in a phyllome. In many plants, hydathodes includes a portion of thin-walled parenchyma between the tracheary elements and the pore, known as an epithem. In some plants, hydathodes are associated with secretory tissue.
hydathode pore [
PO:0025322; plant anatomy term ]
A plant anatomical space that is an opening in a hydathode.
More Synonyms: poro del hidatodo (Spanish), 排水組織孔 (Japanese)
Comments: Similar to a stomatal pore, but lacks the ability to open and close. Involved in the release water or xylem sap through guttation or secretion.
hydroid [
PO:0025032; plant anatomy term ]
A native plant cell (PO:0025606) that is dead at maturity, lacks specialized wall thickenings or lignin, and has tapered ends that are thin and partially hydrolyzed.
More Synonyms: ハイドロイド、仮導管状細胞 (Japanese), hidroide (Spanish), hydroid cell
Comments: Hydroids are water and mineral conducting cells found in bryophytes in axes and leaves in the gametophytic phase and in the seta in the sporophytic phase.
hydrome [
PO:0030047; plant anatomy term ]
A portion of plant tissue (PO:0009007) that has as parts hydroid (PO:0025032) cells and cells of no other types.
More Synonyms: hidromo (Spanish), hydrom, leptoxylem, 導水組織 (Japanese)
Comments: A hydrome is composed of only hydroids. Found in bryophytes, in the center of a non-vascular shoot axis (PO:0025029) such as a gametophore (PO:0030018) or seta (PO:0030032). Often surrounded by the leptome (PO:0030048). May function in water conduction and may provide support.
hypanthium [
PO:0009065; plant anatomy term ]
A cup- or tube-shaped cardinal organ part, bearing perianth and stamens on its rim, so these arise above the base, and often above the top, of the ovary.
More Synonyms: 花床筒 、いちじく状花序(=hypanthodium (Japanese), floral cup, hipantio (Spanish), hypanthia
Comments: Only bears stamens or perianth segments if they are present in the flower (e.g., no stamens in a carpellate flower).
hyperphyll [
PO:0020044; plant anatomy term ]
The unifacial terete apical portion of a monocot cotyledon, sometimes also visible on other leaves.
More Synonyms: hiperfilo (Spanish), 単子葉の単面円柱形先端 (Japanese)
Comments:
hypocotyl [
PO:0020100; plant anatomy term ]
A stem internode (PO:0020142) below the cotyledonary node (PO:0025321) and transitional to a root (PO:0009005) of a plant embryo (PO:0009009) or a seedling (PO:0000003).
More Synonyms: 胚軸 (Japanese), hipocótile (Spanish)
Comments:
hypocotyl endodermis [
PO:0006065; plant anatomy term ]
A portion of endodermis (PO:0000252) that is part of a hypocotyl (PO:0020100).
More Synonyms: endodermis del hipocótile (Spanish), 胚軸内胚葉 (Japanese)
Comments:
hypocotyl epidermis [
PO:0005013; plant anatomy term ]
The outermost primary cell layer of the hypocotyl.
More Synonyms: epidermis del hipocótile (Spanish), 胚軸 表皮 (Japanese)
Comments:
hypocotyl vascular system [
PO:0008015; plant anatomy term ]
Vascular system of the hypocotyl.
More Synonyms: 胚軸維管系 (Japanese), sistema vascular del hipocótile (Spanish)
Comments:
hypocotyl-root junction [
PO:0004724; plant anatomy term ]
A cardinal organ part (PO:0025001) that is the part of a plant axis (PO:0025004) where a radicle (PO:0020031) joins a hypocotyl (PO:0020100).
More Synonyms: embryo axis transition zone, 胚軸-根合流点 (Japanese), Poaceae crown, union del hipocótile con la raíz (Spanish)
Comments:
hypodermis [
PO:0005051; plant anatomy term ]
A portion of ground tissue (PO:0025059) that is the outermost layer of a portion of cortex (PO:0005708).
More Synonyms: 真皮 (Japanese), hipodermis (Spanish), portion of hypodermal tissue
Comments: A layer or layers of cells beneath the epidermis that is distinct in appearance from adjacent tissues.