Mushroom Trivia
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Top Ten

shape words

Terms discussed: acerose, amygdaliform, clavate, cylindrical, dacryoid, fusiform, helicoid, helicospore (pl. helicospores), lacriform, lacrimoid, lanceolate, limoniform, pyriform, reniform, sigmoid, staurospore (pl. staurospores), stellate, subulate, subuliform, tapered, truncate, ventricose, vermiform


Topics:
acerose
amygdaliform
clavate, tapered
dacryoid, lacriform, lacrimoid
equal
fusiform
helicoid
lacriform
lanceolate
limoniform
pyriform
reniform
sigmoid
staurospore
stellate
subulate, subuliform
truncate
ventricose
vermiform

See Also:
umbo
cap shape


      

acerose


Long and straight and pointy on both ends, like a pointy hot dog.

See also fusiform.
      

amygdaliform


Almond-shaped.
Usually used for spores.
       

clavate, tapered



Image of Fomes fomentarius from Jean Louis Émile Boudier (1904 - 1909) Icones mycologicae ou iconographie des champignons de France, principalement Discomycètes
Fomes fomentarius
Club-shaped.
Slightly wider somewhere in the middle than at either end; often the wideness is not quite centered.

An object with this sort of shape will get described differently depending on how much longer than it is wide: something now that is not much longer than it is wide will usually be called clavate, while something that is longer one will be called tapered. In fact, in some cases, clavate shapes (like the hymenium cells in the picture here) are almost ovoid.

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Tapered can also refer to macroscopic structures that are simply wider at one end than the other. Except for this case, clavate and tapered objects can also be called ventricose, although that term also refers to shapes where the swelling is quite sudden, and perhaps irregular. Clavate and tapered are only used in situations where the increase in width is smooth and gradual.

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Image of Odontia from Jean Louis Émile Boudier (1904 - 1909) Icones mycologicae ou iconographie des champignons de France, principalement Discomycètes
Odontia
I will emphasize that only macroscopic structures (usually stems) get called tapered. With hymenial cells, especially, the distinction between a clavate
        

dacryoid, lacriform, lacrimoid


Tear-shaped
     

equal


Perfectly cylindrical. A long object that is exactly the same width throughout.
      

fusiform



Image of Antennaria from Christian Gottfried Daniel Nees von Esenbeck & A. C. F. Henry (1837) Das System der Pilze: part one
Antennaria
This term is used in two senses:
1) Long, coming to a (usually blunt) point at both ends and swelling gradually from them all the way to the middle.
Of the four septate spores lined up at the bottom of the picture, the right-hand two are fusiform in this sense (the extreme right one being a pinwheel of fusiform spores)

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2) The two spores on the left illustrate the other common usage of fusiform: long and coming to a point at both ends, like a pointy hotdog, as in Clavulinopsis fusiformis.

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Many people defining this term give "spindle-shaped" as a synonym. Why they would think this useful, when spindles haven't been in common usage for more than a hundred years now, totally escapes me. For the record, a spindle is shaped like usage number one here.
One can see from the picture why one might want to have both usages available: it means you only have to use one term in describing both spore shapes of this species. However, I believe that the pointy hotdog shape should be designated with the term acerose, which specifically means that shape and only that shape; fusiform can then be reserved for objects that have the "genuine" spindle shape.

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The usage of fusiform (in the first sense) also seems to overlap with the usage of ventricose (in its first sense). The issue there seems to be how gradual the central swelling is. In both cases, the thicker "center" may actually be quite off-center.
And then of course there's amygdaliform...

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helicoid


Spiral-shaped.

A helicoid spore is called a helicospore.
     

lacriform


Tear-shaped
      

lanceolate



Image of Phellinus rimosus from Jean Louis Émile Boudier (1904 - 1909) Icones mycologicae ou iconographie des champignons de France, principalement Discomycètes
Phellinus rimosus
"Lance-shaped". I have the quotation marks because (in spite of the real-life shape of a lance) when this term is used in mycology it tends to denote cells that have a wide, rounded base and come gradually to a point, like the brown setae in this picture of Phellinus rimosus.
For a cell that really is lance-shaped, use subuliform or subulate.

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limoniform


Lemon-shaped
      

pyriform


Pear-shaped
      

reniform


Kidney- or bean-shaped
      

sigmoid


Shaped like the Greek letter sigma, which is sort of like a more vertical letter S.
      

staurospore



Image of Antennaria from Christian Gottfried Daniel Nees von Esenbeck & A. C. F. Henry (1837) Das System der Pilze: part one
Antennaria
A septate spore shaped like a pinwheel. Usually, each branch of the pinwheel is also septate.

The spore at lower right in the picture is a staurospore, as is the one in the middle of the right-hand side, and several of the ones flying off from the stroma.

See also stellate.

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stellate


Shaped like jacks. This is usually used for a non-septate spore which has lots and lots of points on it. This is different from a staurospore, which is septate and is only pointy in two dimensions.
       

subulate subuliform



Image of Cyttaria from Jean Louis Émile Boudier (1904 - 1909) Icones mycologicae ou iconographie des champignons de France, principalement Discomycètes
Cyttaria
Shaped like an awl. Thinner and longer than lanceolate
      

truncate


Smoothly rounded - - egg-shaped or elliptical - - except for one end which looks like it's been lopped off.
      

ventricose



Image of Lactarius piperatus from Joseph Henri Léveillé (1837) Sur le hymenium des champignons in Annales des Sciences Naturelles. Botanique
Lactarius piperatus
Swollen in the middle. This word is used in two senses.
1) The first sense is what you would expect just from reading the definition, as shown in the picture of the protruding, ventricose basidia of Lactarius piperatus.

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2) The term is also used when something is only swollen on one side, giving the ventricose object a profile like a person with a beer-belly. This usage is most often applied to spores. For all other objects, assume the first usage.

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See also fusiform
      

vermiform



Image of Lepiota lutea from Jean Louis Émile Boudier (1904 - 1909) Icones mycologicae ou iconographie des champignons de France, principalement Discomycètes
Lepiota lutea
Worm-shaped. More or less the same as cylindrical, but cylindrical tends to refer to macroscopic structures like caps and stems, and to microscopic structures that are only about one spore long (like spores). Vermiform gets used for microscopic structures that are multicellular, like the protruding cap hyphae (shown in microscopic view at the lower left) in this picture of Lepiota lutea.

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