210 
The Irish NalMralist. 
September, 
lower lake (which is the more characteristic as well as the 
larger portion), and some stunted Chara is usually the only 
other inhabitant of this zone. 
Schcemcs zone. — This extends from summer water-level to 
about two feet above it. Ground wet and marly. Schmius 
nigricans is absolutely dominant, and very abundant. Here 
also Epipactis palustris has its headquarters. This lovely 
Orchid is remarkably common around lyough Carra, and 
hardly a yard of shore, on island or mainland, is without it ; I 
never saw it in such profusion before. Other abundant and 
characteristic plants of the Schaenus zone are Galitmi boreale, 
Cnicns pratensis^ Par7iassia palustris^ Pingnicula zmlgaids^ 
Habcnaria conopsea, Selaginella selagi7ioides. Two interesting 
Orchids, Ophrys apifera and O. 7imscife7^a, seen at Derrinrusli 
and below Moore Hall, grew in this zone, as also Eqniseitmt 
variegatuiii (var. niajtis, Syme), found on Bush Island. 
Sesleria zo7ie. — When the ground reaches about two feet 
above summer water-level (the lake does not appear to be sub- 
ject to much winter flooding), Sesleria ccerulea becomes 
abundant, and as one ascends, quite replaces Schcsnus, grow- 
ing luxuriant and tall (up to 2^ feet), and easily dominant, 
save on one or two islands, where the zone is controlled by a 
tall growth of Festuca elatior. The ground here is dry, and 
masses of disintegrating shells thrown or blown up by .storms 
help to make a light limy soil. Abundant and characteristic 
concomitants of the Sesleria are Thalictmrn colli7iu77i, Viola 
ca7iina^ Rhanmtcs Fra7igula (growing almost prostrate)^ Rjibus 
saxatilis, Galiit7Jt vej'UDi^ A7iten7iaria dioica, Carlijia vulgaris^ 
Leo7itodon hispidics, Cainpa7nila jvtimdifolia, Chlora perfoliafa, 
Pla7itago majdtinia^ Orchis py7a7nidalis, AgrQstis nigra — a very 
calcicole group, it will be noticed. Odd young trees from the 
next zone — mostly Birches — are sometimes present. 
Woodland zo7ie. — At about four feet above summer water- 
level the grass formation gives way abruptly to arboreal vege- 
tation. On shores facing west this presents a very dense 
thicket, sloping upwards from the ground ; on the other side 
the bushes are larger, and their front not so dense. The leading 
species are Betula pubescens, Rhamnus catharticus, Fraxi7ius 
excelsior, Salix anrita, S. ci7iei-ca^ Ju7iiperus co7}wm7iis. There 
are also present Cratcegus Oxyaca7itha^ Ikx Aquifoliu7ny 
