— 30 — 
Complicated Stem-tissue in Polytrichum. — 
Polytrichum has “a central cylinder composed of elongated cells with scanty 
contents, of elements resembling sieve-tubes, and of elongated cells; the three 
kinds of element serve respectively to transport water, albuminous substances, 
and carbohydrates.” — Text-Book of Botany, Strasburger, etc., English Transk 
1912, p. 120. 
Mossworts in Bessey’s College Botany. — In the “Essentials of College 
Botany,” 1914, by Charles E. Bessey and Ernst A. Bessey, the “Mossworts”' 
(Phylum VIII, Bryophyta) receive 12 of the 156 pages of systematic botany,. 
8%. In the Chicago “Textbook of Botany” (1910), Coulter gives the Bryo- 
phytes 11%. In Bergen and Davis’s “Principles” (1906), the proportion is 13%; 
Campbell’s “University Textbook” (1902), 12%; Atkinson’s “College Botany”' 
(1905), 14%; and Strasburger, Jost, Schenck, Karsten’s “Textbook” (Engl. 
Edit., 1912), 5%. Although brief, the treatment in Bessey’s text is clear and 
interesting. 
Bessey’s common names for many of the Mossworts will probably be new 
to many Bryologist readers. They are, stated in their respective order: Ric- 
cias, Hornworts (. Anthoceros ), Great Liverwort ( Marchantia ), Scale Mosses- 
( Jungermanniales ), Black Mosses (Andreaeales) , Peat Mosses (Sphagnales) , and 
True Mosses ( Bryales ). The True Mosses are Top Mosses ( Acrocarpi ) and Side 
Mosses (Pleurocarpi) ; these being Turf Mosses ( Dicranaceae ), Cushion Mosses 
{Leucobryaceae) , Petticoat Mosses ( Splachnum ), Bristle Mosses ( Funariaceae 
and Timmiaceae) , Ephemeral Mosses (. Ephemerum ), Wood Mosses ( Bryaceae and 
Mniaceae), Humpback Mosses (Buxbaumiaceae) , Haircap Mosses ( Polytrich - 
aceae ), Brook Mosses ( Fontinalaceae ), Tree Mosses ( Climaceae ), and Bog Mosses 
(. Hypnaceae ). The names, descriptive either of moss or habitat, are generally 
well-chosen, although “Tree Mosses” is somewhat ambiguous, and “Bog Mosses”" 
will not appeal to moss students in regions with many Hypnaceae but few or no 
bogs. The book ends with an enumeration of the 683 families recognized by 
Bessey, the prominent families being briefly characterized, and the important 
genera mentioned. There are 6 families of Liverworts and 59 of Mosses. 
The systematic sequence of the families of Mossworts is still a disputed 
question, practically all systematists, however, placing first the forms with flat 
thalli, like the Riccias, in which the sporophyte is little more than a mere spore- 
case. For the rest of the Liverworts the classification depends largely on whether 
the main reliance is placed on the characters of the gametophyte or of the sporo- 
phyte, or of both together. Bessey evidently placed most emphasis upon the 
gametophyte. His sequence is Riccia, Anthoceros with its more compact thallus, 
Marchantia with its highly complex thallus, the thalloid and, finally, the leafy 
Jungermanniales. This is inconsistent in that Aneura and Pellia among the 
thalloid Jungermanniales have probably the simplest known liverwort gameto- 
phytes. The rather generally accepted classification in which the sporophyte 
is given more prominence is probably a better one; the order then being Riccia , 
Marchantia , Jungermanniales, and ending with Anthoceros with it's highly com- 
plex chlorophyll-bearing sporophyte. 
