CHARA. 435 



** Stem coated with twice as many tubes as there are branchlets 

 in each whorl, those opposite to the branchlets bearing spines 

 or tubercles, the others not. 



12. C. vulgaris (L. ?) ; monoecious, st. scabrous finely striate 

 brittle, upper part of the branchlets without external tubes, 

 bracts only on the inner side of the branchlets, four long, two 2 4 

 times as long as the nucules, two equalling them. E. B. 336. 

 C.fcetida A. Br., Atl. Fl. Par. 37. Diffuse, usually incrusted. 

 The spinose or tubercular (primary) cortical tubes less prominent 

 than the secondary ones, collapsing when dry so as to place the 

 spines in furrows. Branchlets seeming of one joint. Nucules 

 with 13 striae and a short crown, with the globule. Ditches and 

 streams. A. VI. VIII. 



13. C. hispida (L.); monoecious, st. thickened upwards spirally 

 sulcate rough brittle with setaceous spines, branchlets long, 

 bracts whorled (inner ones longer), nucules ovate shorter than the 

 bracts solitary with a globule. E. B. 436. Atl. FL Par. 38 B. 

 Opaque, greenish-white, usually incrusted. St. covered with 

 minute tubercles ; spines very many, sometimes few, upon the 

 depressed primary tubes. Branches long, acuminate, of 7 joints, 

 with 4 5 short bracts at each joining. Ditches and pits. A. 

 V. VIII. 



14. C. tomentosa (L.) ; dioecious (?), st. thickened upwards 

 spirally sulcate rough brittle with scattered obtuse papillce, 

 branchlets incurved, bracts unilateral ovate-oblong mucronate- 

 acute, nucule shorter than the bract on each side of it longer 

 than the three in front. C. latifolia Willd., Hook. Icon. 532. 

 Opaque, whitish-green. St. covered with minute tubercles ; pa- 

 pillae distant, rather whorled, short, blunt, on the prominent pri- 

 mary tubes. Belvidere Lake, Westmeath, Ireland. A. VII.? I. 



*** Stem coated with 3 times as many tubes as there are branchlets 

 in each whorl, two rows of secondary between each pair of 

 primary tubes on which latter alone the spines or tubercles 

 are placed. 



15. C. aspera (W .) -, dioecious, st. finely striate smooth flexible 

 with setaceous patent spines, branchlets short, bracts whorled 

 slender (2 inner longer), nucules narrowly oblong shorter than 



. the bracts. E. B. S. 27381 Not opaque, pale green. St. densely 

 crowded ; spines scattered, often very short, or irregularly 

 whorled. Branchlets 6 9 in a whorl, of 7 joints, 4 5 bracts 

 at each joining. Nucules solitary, striae 12 or 13, crown pro- 

 minent. Stagnant water. A. VIII. 



16. C.fragilis (Desv.) ; monoecious, st. slender finejy strLte 



u2 



