**Core Concept**
Datura poisoning is caused by the ingestion of plants containing tropane alkaloids, such as scopolamine and hyoscine. These compounds act as anticholinergic agents, leading to a range of systemic effects.

**Why the Correct Answer is Right**
The key features of Datura poisoning include mydriasis (pupil dilation), tachycardia, dry mouth, and delirium. Anticholinergic effects are mediated through the inhibition of acetylcholine at muscarinic receptors, leading to decreased parasympathetic activity. This results in the characteristic symptoms of Datura poisoning.

**Why Each Wrong Option is Incorrect**
**Option A:** Mydriasis is a feature of Datura poisoning, as it is caused by the inhibition of parasympathetic activity, leading to increased sympathetic tone and pupil dilation.

**Option B:** Delirium is a feature of Datura poisoning, as the anticholinergic effects of scopolamine and hyoscine can lead to altered mental status and confusion.

**Option C:** Dry mouth (xerostomia) is a feature of Datura poisoning, as the decreased parasympathetic activity leads to reduced salivation.

**Option D:** Hypotension is not a feature of Datura poisoning. In fact, tachycardia and hypertension are more common due to the increased sympathetic tone caused by anticholinergic effects.

**Clinical Pearl / High-Yield Fact**
In the context of Datura poisoning, it's essential to remember that the anticholinergic effects can be reversed with physostigmine, a cholinesterase inhibitor.

**Correct Answer: D. Hypotension is not a feature of Datura poisoning.**