Introduction to Narrow-leaved Pondweed Identification

This video is the second in the 2022 series of aquatic plant identification webinars - part of the BSBI's Irish Aquatic Plants Project, supported by NPWS. Expert Nick Stewart presents Introduction to Narrow-leaved Pondweed Identification.

00:00 Introduction
03:28 Books and other resources
05:51 Features of pondweeds
08:20 Narrow-leaved pondweeds
10:13 Group 1 of narrow-leaved pondweeds - with sheathing base to leaves
10:14 Stuckenia pectinata and S. filiformis
14:29 Ruppia - the Tasselweeds
18:22 Group 2 of narrow-leaved pondweeds - leaf blade arises directly from the node
20:12 Leaves less than 2mm wide with tapered tips
20:22 Potamogeton trichoides
21:46 P. rutilus
23:17 Leaves less than 2mm wide with abrupt tips
23:29 P. berchtoldii and P. pusillus
25:03 How to check stipules
30:07 Nodal glands
31:29 Turions
34:15 Abruptly pointed leaves to acute or obtuse tips
35:38 Leaves 2-6mm wide without numerous vein-like strands
37:01 P. friesii and P. obtusifolius
41:06 Leaves 2-6mm wide with numerous vein-like strands
42:22 P. acutifolius and P. compressus
44:50 Leaves more than 6mm wide - P. crispus
46:37 P. epihydrus
49:44 Species found in Ireland
50:28 Species found in Scotland
51:06 Species found in England and Wales