56 HISTOKY OF BRITISH PEENS. 



II. LYCOPODIACE.E. 



xix. LYCOPODIUM, Linn&us. 



1. L. alpinum, Linnam. Leaves in four rows, ap- 



pressed ; spikes solitary, sessile. 



2. L. Selago, Linnceus. Leaves in eight rows, imbri- 



cated on the usually erect stems ; fructifications 

 in the axils of leaves, not spiked. PL XX. fig. 5. 



3. L. annotinum, Zfinnceus. Leaves indistinctly five- 



rowed, linear-lanceolate, patent; spikes solitary, 

 sessile. 



4. L. clavatuin, Itinnteus. Leaves scattered, incurved, 



hair-pointed; spikes two or more on a stalk. 

 Plate XX. fig. 6. 



5. L. inundatum, Linntzus. Leaves scattered, curved 



upwards, linear; spikes solitary, sessile. Plate 

 XX. fig. 4. 



6. L. selaginoides, Linnaus. Leaves scattered, half- 



spreading, lanceolate; spikes solitary, sessile. 



III. MAESILEACE.E. 



xx. ISOETES, I/inntem. 



1. I. lacustris, Linnteus. The only species. Plate 

 XIX. fig. 1. 



