Myriophyllum.] halouagace^. 175 



Aquatio plants, with whorled leaves and the aspect of some Equisetum, Ihouga 

 not in the remotest degree related to that cryptogamic genus. The species are 

 very few, and confined to the colder parts of the globe. 



1. H. vulgaris, L. Common Mare's-tail. Leaves many (6 — 

 12) in a whorl, linear. Sin. E. Fl. i. p. 4. Br. Fl. p. 138. E. 

 B. t. 763. Curt. Fl. Lond. ii. fasc. 4, t. 1. 



In ponds, ditches and slow streams ; very rare. Fl. May — July. Fr. July, 

 August. %. 



E. Med. — Marsh-ditches between Brading and Si. Helen's, plentifully, Ed. 

 Hart Vinen, Esq., and Mr. W. Turner .'.'.' 



Herb quite smooth in every part. 8tem simple orslightly branched, jointed, filled 

 with a beautiful network of large angular cells, arranged in circles around a cen- 

 tral medullary chord ; procumbent and rooting at each division, with bundles of 

 long white fibres ; afterwards erect, and rising above the water as the flowering 

 advances to a foot or higher. Leaves in whorls of 6 — 12, sessile, linear, fleshy, 

 single-ribbed, quite entire (except a lateral curved tooth on a few here and there 

 occasionally), glabrous, ending in a small hard point ; the submerged leaves 

 remaining all the winter are thin, pale green, membranous and deflexed, greatly 

 like the subaqueous ones of Callitriche : those above the surface are bright green, 

 thick and curving upwards. Flowers solitary at the insertion of each leaf. An- 

 ther large, 2-celled, reddish ; Jilament inserted on the ovarium in fiont of the style, 

 at first very short but afterwards elongating considerably. Ovarium turbinate, 

 bearing on its upper and back part a very short conical style, and long, white, 

 tapering stigma, much like that of some Carex. 



The French call this herb Pesse d'eau, from its resemblance to a pine-tree in 

 miniature. 



II. Myeiophyllum, Linn. Water Milfoil. 



" Monoecious. Barren flowers : — Calyx inferior, of 4 leaves. 

 Petals 4. Stamens 4 — 8. Fertile flov)ers : — Calyx 4-lobed. Pe- 

 tals 4. Stamens 4 — 8, or wanting. Stigmas 4, sessile. Fruit of 

 4 sessile, subglobose, 1-seeded carpels, at length separating." — 

 Br. Fl. 



1. M. spicatum, L. Spiked Water Milfoil. Leaves mostly in 

 whorls of 4 together, the segments setaceous mostly opposite or 

 subalternate. Br. Fl. p. 139. E. B. t. 83. Fl. Dan. iv. t. 681 

 bona). 



In ditches, pools and clear slow streams : frequent. Fl. May — September. 



E. Med. — Very abundantly in ditches on Sandown marshes, as in those about 

 the fort, and by the road before coming to the village from Brading. Ditches at 

 the foot of Alverston lynch. Ditches on Brading marshes, abundantly. Ditch 

 by Yarbridge. 



W. Med.— 'Seal- Colwell. 



Root a tuft of long, slender, brittle fibres, running deep into the soft mud. 

 Stems branched, various in length, round, reddish, succulent, the interior beauti- 

 fully filled up with radiating septa forming large oblong cells, rooting here and 

 there occasionally at the joints, and often exceeding a crow-quill in thickness. 

 Leaves in whorls of 4 together at each joint of the stem, finely pectinated, the seg- 

 ments setaceous, a few of the lower usually truly opposite, the rest imperfectly so 

 or somewhat alternate, a little swollen at the base from a glandular prominence in 

 the axil of each segment, scarcely if at all observable in the next species, in which 

 the segments of the leaves are not only more decidedly alternate, but less nume- 

 rous and farther apart. Spikes 3 to 5 inches long, erect or reclining on the sur- 



