TYPHACE 165 
2. [YPHA, L. 
Spikes very dense, brown, cylindrical, with deciduous 
leafy bracts; stamens several ; monadelphous; ovaries 
stalked, often imperfect. 
I. latifolia, L., Greater Reed-Mace (often called Bul- 
rush); stem 3-6 ft., spikes 6-12 in. long, I in. diameter ; 
ditches and ponds, frequent. Z. angustifolia, L., Smaller 
Reed-Mace ; leaves narrower, spike 4-2 in. diameter, not 
continuous; not so common. TZ. minima, Hin. (Lax- 
mannt, Lep.); stem 1-3 ft., stem-leaves very small, 
scale-like; water-sides, occasional. TZ. Shuttleworthit, 
Koch; inflorescence composed of two contiguous grey 
spikes; Switzerland, Dauphiny, occasional. 
Order XCIII.—NAIADE&. 
Flowers unisexual or bisexual, inconspicuous ; perianth 
0 or 3-4-lobed, inferior ; ovary of 1-4 carpels, with one 
Seed in each carpel.. Aquatic or marsh plants, usually 
with floating leaves sheathing at the base. 
I. POTAMOGETON, L. 
Flowers bisexual, in axillary or terminal spikes; peri- 
anth-segments 4, green; stamens 4; carpels usually 4; 
leaves submerged and translucent, or floating and opaque, 
often with connate stipules. 
No species of Pond-Weed are truly alpine, though some 
are found at considerable altitudes. The species are often 
difficult to distinguish, and require more minute descrip- 
tions than can be given here. The following are given 
