LTCOPODIAOE^. 615 



LXXXIX. CLUBMOSS FAMILY. LTCOPODIACE^. 



Leaves radical or alternate, undivided in the British genera. 

 Spores enclosed in capsules, sessile or nearly so, either at the 

 base or in the axils of the leaves, or forming a terminal spike 

 interspersed with leaf-like bracts. 



Aquatic plants, with linear, grass-like, radical leaves. 



Stock tufted. Fructification in the thickened base of the leaves . , 1. Quillwoet. 



Rootstock creeping. Capsules globular, in the axUs of the leaves , 2. Pillwokt. 



Terrestrial plants, with the leaves usuuUy short and crowded .... 3. Clubmoss. 



I. QUILLWORT. ISOETES. 



Stock very short, rooting at the base, bearing a tuft of hnear leaves, the 

 ■whole plant usually under water. Capsules more or less enclosed within 

 the enlarged base of the leaves, those of che inner leaves filled with minute 

 powdery granules, those of the outer leaves containmg larger grains, at 

 first coher'ing in fours. 



A small genus, widely spread over the greater part of the globe. 



1. European Quill^rort. Xsoetes lacustris, Linn. 

 (Eng. Bot. t. 1084.) 



A perennial, of a bright green, forming dense tufts under the water. 

 Leaves narrow-lmear, much like those of several Monocotyledons, varying 

 from 2 to 6 inches long, their enlarged bases giving the plant often a 

 bulbous appearance. 



In mountain pools, and shallow lakes, in central and northern Europe, 

 northern and Arctic Asia, and North America. In Britain, in the moun- 

 tainous parts of Scotland, northern England, Wales, and Ireland. Fr. 

 summer and autumn. 



II. PILLWORT. PILULAEIA. 



Kootstock creeping under water, with subulate leaves almost solitary at 

 the nodes. Capsules globular, aknost sessile in the axils of the leaves, 

 divided into 4 cells, opening when ripe, at the top, in 4 valves, and contain- 

 ing very minute powdery granules and some larger grains. 



The genus consists but of a single species. 



1. Creeping' PillTirort. Pilularia globulifera, Linn. 



(Eng. Bot. t. 521.) 



The slender rootstock often creeps to a considerable extent, rooting at 

 every node. Leaves very fine, bright green, usually 2 or 3 inches long. 

 Capsules hke little pLUs, near 2 lines diameter, and covered with short hairs. 



In the shallow edges of pools and lakes, in temperate Europe and western 

 Asia ; not recorded either from the Arctic or the Mediterranean regions. 

 Widely distributed over Britain, and in some places not uncommon, but 

 often overlooked. Fr. summer and autumn. 



III. CIiUBMOSS. LYCOPODirM. 

 Perennials, with a branched, usually creeping stem, crowded with small. 



