Classification of Green Algce. 163 
Karlier in the year there are the trees with their catkins, a mark of 
kinship, and the stipules transient structures merely for bud-protection. 
Caryophyllaceae again (call it Stitcliwort and Campion family), what 
obvious characters the members have in common, falling at the same 
time into two sets, the open-flowered (you need not call it Alsineae; and 
the tubular. And then you can bring in the insects. 
These are a few examples taken at random, but the store is 
inexhaustible, for as you go on you find you can go deeper. A few terms 
are necessary, but sepals, petals and stamens are not very dreadful, and 
stipules no more appalling than cotyledons. A wise teacher will see when 
the little brains are beginning to fog over, and stop. And of course he 
will not dwell on exceptions, which by the way are not by any means 
peculiar to systematic work. It is possible to cavil even at the simple 
statement that “ a seed does not germinate unless it is damp and 
warm”—what do you mean by damp ? what doyoumean by warm?—except 
when the ground is hard with frost, the ditch-sides are green with seed¬ 
lings of cleavers, and the driest, dirtiest of road-sides will supply some 
specimens. 
Without depreciating other methods I think, Sir, that I have illus- 
strated one, which is not over-burdened with technical terms, requires no 
apparatus, and has the great advantage of systematising the facts which 
are observed. 
Believe me, 
British Museum (Nat. Hist.), Yours truly, 
July yd, 1902. A. B. RiCNDLK. 
A REVISION OF THE CLASSIFICATION OF 
THE GREEN ALGJB 
BY 
F. F. Blackman, 
University Lecturer in Botany, Cambridge. 
AND 
A. G. Tansley, 
Assistant Professor of Botany, University College, London. 
{continued from page 144.) 
Fam. VIII. COI.EOCHAETACEAE. 
Thallus generally epiphytic , consisting of an attachment-plate 
which is a more or less concrescent branch-system (sometimes pseudo- 
parenchymatous) with or without erect free vegetative branches. Some 
cells of the attachment-plate or of the erect branches bear characteristic 
stout stiff sheathed “setae” with a definite lumen. Cells, cylindrical 
or polygonal by compression, with a single large parietal chloroplast 
and one pyrenoid. 
Reproduction by bi-flagellate zoospores and by oogamy. Oogonium 
terminal, flask-shaped, opening by a long neck and containing a single 
spherical egg with a large chloroplast. Antlierozoids oval, bi-flagellate, 
devoid of chlorophyll. After fertilisation the oogonium becomes 
invested with a single-layered “cortex” of concrescent thallus-branches 
which mptures on germination. 
