152 HALORAGE^E. [Myriophyllum. 



1. M. verticilla'tum, L. ; spike erect in bud, floral leaves all whorled 

 in about fives pinnatifid or pectinate all longer than the flowers, upper 

 axils usually flowerless. 



Ditches and ponds, from Cumberland to Kent and Somerset ; Ireland, rare ; 

 Channel Islands ; fl. July-Aug. — Rootstock creeping. Steins floating, leafy. 

 Leaves 1-2 in ., in close-set whorls; segments distant, capillary, collapsing 

 when removed from the water. Spike elongate. Flowers white. Anthers 

 linear. Fruit subglobose, green, carpels rounded on the back. — Distrib. 

 Europe, N. Africa, N. and "YV. Asia, India, N. America. 



Var. M. pectina'tum, DC. has very short floral leaves. 



2. M. alterniflo'rum, 1)0. ; spike curved at the tip in bud, female 

 floral leaves whorled in threes or fours pectinate longer than the flowers, 

 male opposite or alternate entire or serrate shorter than the flowers. 

 Ponds and ditches, from Shetland to Cornwall and Sussex ; ascends to 1,200 ft. 



in the Highlands ; Ireland ; Channel Islands ; fl. June-Aug. — Habit of M. 

 spicatum, but more slender and flowers fewer, and inhabits lakes in 

 hilly and upland districts. — Distrib. Europe (Arctic), N. Africa, Arctic 

 America. 



3. M. spica'tum, L. ; spike erect in bud, floral leaves all whorled in 

 about fours pectinate shorter than the flowers. 



Ponds and ditches, from Orkney to Devon and Kent ; ascends to 1,200 ft. in 

 the Highlands ; Ireland ; fl. June-Aug. — The small floral leaves, giving the 

 inflorescence a more spicate appearance than M. verticillatum, is its best 

 character ; the fruit also is less globose. — Distrib. Europe (Arctic), N. 

 Africa, N. and "W. Asia, India, N. America. 



3. CALLITRICHE, L. WATER STAR-WORT. 



Slender glabrous marsh or aquatic plants. Leaves opposite, quite entire, 

 upper often rosulate. Flowers unisexual, minute, solitary, axillary. — 

 Male fl. Perianth 0. Stamen 1, subtended by two caducous bracts, fila- 

 ments slender ; anther-cells confluent above. — Female fl. Bracts 2 or 0. 

 Ovary sessile or shortly peduncled, 4-lobed longitudinally, 4-celled ; styles 

 2, slender, stigmatose all over. Fruit compressed, 4-lobed, 4-celled, lobes 

 angled margined or winged at the back, at length separating, indehiscent. 

 — Distrib. Chiefly temp, waters ; species 3 or 4. — Etym. kclXos and 0pl|, 

 from the elegance of its capillary ramification. — I have followed Hegel - 

 maier's limitation of the British forms of this very variable genus. Its 

 affinities are very doubtful. 



1. C. ver'na, L. ; leaves not dilated at the base, flowers bracteate, 

 carpels slightly keeled connate for about half their breadth. 

 P.mds, ditches and sluggish streams, from Shetland southd. ; ascends to 

 2 : 200 ft. in the Highlands ; Ireland ; Channel Islands ; fl. April-Oct.— 

 Very variable in size and habit, covered with scattered stellate hairs or 

 scales. Stems 3-12 in., submerged, terete, sparingly branched. Leaves 

 |-1 in., submerged linear; floating rosulate, obovate, notched, 3-nerved. 

 Mowers, male and female often in opposite axils. Bracts white, deciduous, 



