rostellum

American  

[ro-stel-uhm] / rɒˈstɛl əm /

noun

rostella plural

1. Biology. any small, beaklike process.

2. Botany. a beaklike modification of the stigma in many orchids.

3. Zoology.

   1. a projecting part of the scolex in certain tapeworms.

   2. a part of the mouth in many insects, designed for sucking.

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rostellum British  

/ rɒˈstɛləm /

noun

1. biology a small beaklike process, such as the hooked projection from the top of the head in tapeworms or the outgrowth from the stigma of an orchid

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Other Word Forms

Derived Forms

• rostellate
  adjective

Inflected Forms

Nouns

• rostella
  plural

Etymology

Origin of rostellum

1750–60; < New Latin; Latin: little beak, snout, diminutive of rōstrum snout ( see rostrum); for formation, see castellum

Example Sentences

See Examples For:

rostellum

I will say nothing about the rostellum, stigmatic utriculi, fertility of Acropera and Catasetum, for I am completely bewildered: it will rest with you to settle these points by your excellent observations and experiments.

From More Letters of Charles Darwin — Volume 2 by Darwin, Francis, Sir

Read Asa Gray in 2nd Review of my Orchis book on pollen of Gymnadenia penetrating rostellum.

From More Letters of Charles Darwin — Volume 2 by Darwin, Francis, Sir

With Spiranthes autumnalis, the pollen-masses cannot be applied to the stigma until the labellum and rostellum have moved apart, and this movement is very slow.

From Effects of Cross and Self Fertilisation in the Vegetable Kingdom by Darwin, Charles

I have been much interested by what you say on the rostellum exciting pollen to protrude tubes; but are you sure that the rostellum does excite them?

From More Letters of Charles Darwin — Volume 2 by Darwin, Francis, Sir

In Gymnadenia tridentata, according to Asa Gray, the anther opens in the bud, and the pollen being somewhat coherent falls on the stigma and on the rostellum which latter is penetrated by the pollen-tubes.

From More Letters of Charles Darwin — Volume 2 by Darwin, Francis, Sir