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haustorium pl. haustoria |
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STRUCTURE |
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An absorbing and anchoring organ, often root-like, excrescent from a vegetative part of a parasitic or hemiparasitic plant, by which the plant communicates intimately with and derives sustenance and support from its host plant, into whose tissues the haustorium intrudes. |
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head |
= capitulum |
nominative |
inflorescence |
Having crowded, sessile or subsessile, small flowers (florets) borne upon an expanded, distally plane or convex, sometimes paleate, compound receptacle (torus), often with a surrounding involucre, and sometimes a subtending calyculus; characteristic of Asteraceae (Compositae). |
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head-shaped |
= capitate, capitiform |
solid shape |
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Basically globose and resembling a head in the context of occurrence. |
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headed 1 |
= capitate |
architecture |
inflorescence |
Comprising one or more capitula. |
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headed 2 |
= capitate |
solid shape |
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Abruptly enlarged distally to a relatively short, terminal portion that is basically round in transverse section. |
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headless 1 |
= acephalous |
architecture |
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Not terminated or surmounted by a head-like structure, esp. when one might be expected. |
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headless 2 |
= acephalous |
solid shape |
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Not terminating in a head-like portion, esp. when one might be expected. |
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heart-shaped 1 |
= cordate |
base |
laminar structure |
Having two equal, more or less rounded, retrorse lobes, one to either side, overlapping or not, the intervening sinus relatively deep. |
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heart-shaped 2 |
= cordate |
plane shape |
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Fairly regularly attenuate from a broad, bilobate base to a narrow apex, the lobes large, rounded, retrorse, and intersecting; like the stylized outline of the broad lateral face of a heart. See also obcordate. |
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heart-shaped 3 |
= cordiform |
solid shape |
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Having two rounded basal lobes, broadest near the base and fairly regularly attenuate to an essentially angular apex; like the stylized form of a heart. See also obcordiform. |
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heartwood |
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STRUCTURE |
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The senescent inner or central portion of the wood (xylem) of an older stem or root, its cells no longer living, in which conduction has ceased and primary reserve materials are no longer stored; often containing terminal metabolic products; usually darker in color than the living, conducting sapwood that encircles it. |
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helical 1 |
= acyclic, spiral |
arrangement |
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Disposed helically about and along the axis, each on a different radius than the one(s) vertically adjacent. |
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helical 2 |
= spiral |
course |
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Curving with regularly increasing radius from one end to the other in one general plane. |
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helical 3 |
= spiral |
course |
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Curving with constant or regularly increasing radius from one end to the other through three dimensions. |
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helicoid cyme |
= bostryx; > cincinnus |
nominative |
inflorescence |
A cyme in which each axial segment branches to only one side, and all branch to the same side, the whole thus appearing to have an elongate main axis that curves or coils toward its unbranched side. See also scorpioid cyme. |
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helicoid-cymose |
> cincinnate |
architecture |
inflorescence |
Comprising one or more helicoid cymes. See also scorpioid-cymose. |
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helmet-shaped |
= galeate, galeiform |
solid shape |
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Convex overall with a more or less smoothly curved apex, relatively thin-walled and essentially hollow with the interior open to one side below the distal portion; resembling a helmet. See also hood-shaped (cucullate, cuculliform), which overlaps conceptually. |
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hemianatropous |
= amphitropous |
orientation |
ovule |
Having the funiculus adnate to the proximal portion of the (straight) ovule, the latter lying and the micropyle facing parallel to the ovary wall (placenta). |
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hemiepiphytic |
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habit |
plant |
Partially epiphytic; rooted in the ground but with stems growing upon and supported mainly by other plants. |
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hemiparasitic |
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nutrition |
plant |
Partially parasitic; facultatively heterotrophic to a limited degree and capable of obtaining a portion of its essential nourishment directly from other living organisms, to which no reciprocal benefit accrues. |
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hemispheric(al) |
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solid shape |
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Half-spheric(al); broadest at the base and uniformly rounded to the apex, circular in any transverse section, and half-circular in any median longitudinal section. |
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hepta… |
= seven-… |
prefix |
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Indicating presence of or constitution by seven entities of the type denoted by the term's stem; as in heptacolpate, heptafoliolate, heptapterous. |
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herb |
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nominative |
plant |
Annual, biennial, or perennial with no woody (lignified) tissue in any part of the shoot; when persisting over more than one growing season, the parts of the shoot dying back seasonally. |
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herbaceous 1 |
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habit |
plant |
Having no significant degree of secondary growth in any part of the shoot, which thus does not develop woody (lignified) tissue. |
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herbaceous 2 |
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texture |
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Composed entirely of relatively soft, non-woody (unlignified) tissues derived from primary growth. |
