INTRODUCTION TO MOSS IDENTIFICATION
This was on e-bay one time. (I should have grabbed it while I had a chance!)
The place of mosses in the plant kingdom
The plant kingdom is divided into a number of “Divisions” (the equivalent of phyla in the animal kingdom). There are about 10 to 13 divisions recognized, the exact number depending on how much the particular person doing the recognizing lumps or splits divisions. Note: the most modern treatments also have moved things around a bit, too. For example, horsetail/scouring rush (Equisetum) is now classified as a true fern. This figure from a really good introductory biology textbook, Biology: Concepts and Connections by Campbell, Reece, Mitchell and Taylor, shows a simplified phylogeny (evolutionary tree) of plants. Notice that the group labelled “bryophytes” evolved before the other plant groups, i.e., prior to the development either of vascular tissue or seeds.
Here in Ohio we have most, but not all, of the world’s major plant groups represented as wild components of our flora. (We lack psilophytes, gnetophytes, cycads, and ginkgo). The ones we have are:
- Flowering plants (angiosperms), are the “superstars of the plant kingdom. They produce seeds enclosed in an ovary, which develops into a fruit when ripe. Angiosperms are the only plants that produce true flowers.
- The only gymnosperms in Ohio are conifers. Consisting mainly of needle-leaved evergreen trees, these produce “naked” seeds (i.e., seeds not enclosed in an ovary) at the base of woody scales arranged in a spiral: the familiar “pine cone.”
- Ohio has several types of seedless vascular plants (ferns and “fern allies”), namely horsetails/scouring rushes, clubmosses, spikemosses, quillworts and –the most abundant and familiar group –ferns.
- There are three groups of bryophytes. Division Anthocerotophyta are the hornworts, Marchantiophyta comprises liverworts, and Bryophyta are mosses.
Plant divisions in Ohio
Bryophytes are non-vascular plants with a dominant gametophyte
To understand mosses, it helps to understand the plant life cycle. Some terms:
- An organism or a cell that is DIPLOID has two sets of chromosomes in each one of its cells. One set came from its mother and the other set from its father. A familiar example of something diploid is an animal. Sporophyte plants (explained below) are also diploid.
- An organism or a cell that is HAPLOID has one set of chromosomes. Familiar examples are an egg and a sperm. Spores, and also gametophyte plants (explained below) are haploid .
- A GAMETE is a haploid single cell that must fuse with another gamete to continue a life cycle. Eggs and sperm are gametes. A fertilized egg (which is diploid) is sometimes called a ZYGOTE.
- A SPORE, like a gamete, is a haploid single cell, but unlike a gamete, a spore can develop into a multicellular organism all by itself (no fusing required).
The plant life cycle includes the alternation of generations between two different multicellular organisms, either of which might rightly be called a “plant.” These two “generations” are the SPOROPHYTE and the GAMETOPHYTE.
A diploid SPOROPHYTE (i.e., a spore-producing plant) produces haploid SPORES, each of which develops into a multicellular haploid GAMETOPHYTE (i.e., gamete-producing plant). Each gametophyte plant produce haploid GAMETES that fuse together to develop eventually into a multicellular diploid SPOROPHYTE. It’s a cycle! Around and around! I’m getting dizzy!
Here’s a very simple sketch, done by hand to introduce a human element, as if this is a real person talking, not just some anonymous god-like entity in the cyberwebs. We could have made a fancy drawing with Photoshop that looked all professional, or stuck in another ripped-off textbook figure and thus risked doing even more time in the copyright infringement row of the Franklin County Jail. But this is down to earth. Terra firma. Chill. Ahhh. Hi. Kick your feet up and relax. Stay a spell. Everything above the horizontal line is DIPLOID; below the line is HAPLOID. The big circle-ish things are multicellular plants.
Alternation of generations (plant) life cycle
Over evolutionary time, there’s been a trend for plants to develop sporophytes that are larger and more important ecologically that their gametophytes. For plants other than bryophytes, when you see “the plant,” you’re seeing the sporophyte. A fern is a sporophyte, as is a pine tree or a daisy. But for the primitive bryophytes, it’s the other way around. The green, leafy space-occupying entity that competes with other plants is the gametophyte. The bryophyte sporophyte is usually smaller, and simple, looking like a mere appendage of the gametophyte, to which it is permanently attached. The bryophyte sporophyte lives as a parasite upon the maternal gametophyte that produced it. The picture below is of a common log moss, Entodon cladorhizans, showing both stages of the life cycle.
Entodon is a common moss on logs that often develops sporophytes.
Utangulizi wa Ugunduzi wa Mosi Hii ilikuwa kwenye e-bay mara moja. (Lipaswa niichukue nilipokuwa na nafasi!) Mahali pa mwani katika ufalme wa mimea Ufalme wa mimea umegawanywa katika idadi ya <unk>Divisions<unk> (sawa na phyla katika ufalme wa wanyama). Kuna takriban 10-13 mgawanyiko kutambuliwa, idadi halisi inategemea jinsi mtu fulani kufanya kutambua makundi au kugawanyika. Kumbuka: matibabu ya kisasa pia yamehamisha mambo kidogo, pia. Kwa mfano, sasa mti wa horsetail (Equisetum) umegawanywa katika jamii ya fern. "Kama ilivyoelezwa katika kitabu cha kwanza cha ""Biology: Concepts and Connections"" cha Campbell, Reece, Mitchell na Taylor, mimea ni ""mti wa mageuzi.""" Ona kwamba kikundi kilichoitwa <unk>bryophytes<unk> kilitokea kabla ya vikundi vingine vya mimea, yaani, kabla ya maendeleo ya tishu za mishipa au mbegu. Hapa katika Ohio tuna wengi, lakini si wote, ya dunia'majeshi makubwa ya mimea kuwakilishwa kama vipengele mwitu wa mimea yetu. (Hatuna psilophytes, gnetophytes, cycads, na ginkgo). Wale tuna ni: - Mimea ya maua (angiosperms), ni <unk>superstars ya ufalme wa mimea. Wao hutokeza mbegu zilizo ndani ya yai, ambazo zinakua na kuwa matunda zinapokomaa. Mimea ya Angiosperm ndiyo pekee inayotokeza maua ya kweli. - Mimea pekee ya gymnosperms katika Ohio ni conifers. Miti hii ina mbegu za kawaida (kama vile mbegu za majani) kwenye msingi wa magamba ya mbao yaliyopangwa kwa mviringo: Ohio ina aina kadhaa za mimea ya mishipa isiyo na mbegu (ferns na ferns allies), yaani horsetails, clubmosses, spikemosses, quillworts na ferns. - Kuna vikundi vitatu vya viumbe wanaoitwa bryophytes. Idara ya Anthocerotophyta ni hornworts, Marchantiophyta inajumuisha liverworts, na Bryophyta ni mosses. Bryophytes ni mimea isiyo ya mishipa ya damu na gametophyte inayoongoza, ambayo inasaidia kuelewa mzunguko wa maisha ya mimea. Baadhi ya maneno: - Kiumbe au chembe ambayo ni DIPLOID ina seti mbili za chromosomes katika kila moja ya chembe zake. Mfumo mmoja ulitoka kwa mama yake na mwingine kutoka kwa baba yake. Mfano unaojulikana wa kitu diploid ni mnyama. Mimea ya sporophyte (iliyoelezwa hapa chini) pia ni diploid. - Kiumbe au chembe ambayo ni HAPLOID ina seti moja ya chromosomes. Mifano inayojulikana ni yai na shahawa. Spora, na pia mimea ya gametophyte (iliyoelezwa hapa chini) ni haploid. - GAMETE ni chembe moja ya haploid ambayo lazima iunganishwe na gamete nyingine ili kuendelea na mzunguko wa maisha. Mayai na shahawa ni gameti. Nyakati nyingine yai lililotengenezwa kwa mbegu (ambalo ni diploid) huitwa ZYGOTE. - SPORE, kama gamete, ni haploid chembe moja, lakini tofauti na gamete, spore inaweza kuendeleza katika viumbe multicellular yote yenyewe (hakuna fusi zinahitajika). Mzunguko wa maisha ya mimea ni pamoja na mabadiliko ya vizazi kati ya viumbe viwili tofauti vya seli nyingi, ambayo yoyote inaweza kwa haki kuitwa "mimea". vizazi hivi viwili ni SPOROPHYTE na GAMETOPHYTE. SPOROPHYTE ya diploid (yaani, mmea unaozalisha spora) hutokeza SPORES za haploid, kila moja ambayo huendelea kuwa GAMETOPHYTE ya haploid ya seli nyingi (yaani, mmea unaozalisha gamete). Kila mmea wa gametophyte hutokeza GAMETES za haploid ambazo huungana pamoja ili hatimaye kusitawi kuwa SPOROPHYTE ya diploid yenye chembe nyingi. Ni mzunguko! Pande zote na pande zote! Ninaanza kuzunguka! Hapa ni mchoro rahisi sana, kufanyika kwa mkono kuanzisha kipengele cha binadamu, kama kama hii ni mtu halisi kuzungumza, si tu baadhi ya wasiojulikana mungu-kama kitengo katika cyberwebs. """Tungeweza kufanya mchoro wa kifahari na Photoshop ambao ulionekana kuwa wa kitaaluma, au kukwama katika sura nyingine ya kitabu cha masomo kilichovunjwa na hivyo kuhatarisha kufanya muda zaidi katika safu ya ukiukaji wa hakimiliki ya Gereza la Kaunti ya Franklin." Lakini hii ni chini ya ardhi. Kampuni ya Terra. Jihadharini. Ahhh. (Kushangaa) Hebu. Piga miguu yako juu na kupumzika. Kukaa uchawi. Kila kitu kilicho juu ya mstari wa usawa ni DIPLOID; chini ya mstari ni HAPLOID. Mimea mikubwa yenye umbo la mduara ni ya chembe nyingi. Mabadiliko ya vizazi (mimea) mzunguko wa maisha Zaidi ya wakati wa mageuzi, kumekuwa na mwenendo wa mimea kuendeleza sporophytes ambayo ni kubwa na muhimu zaidi kiikolojia kwamba gametophytes yao. Kwa mimea mingine isipokuwa bryophytes, wakati unaona <unk>mti,<unk>unaona sporophyte. Fern ni sporofiti, kama vile mti wa msonobari au daisy. Lakini kwa bryophytes ya awali, ni kinyume chake. Kiumbe chenye majani ya kijani-kibichi kinachochukua nafasi na kushindana na mimea mingine ni gametophyte. Bryophyte sporophyte ni kawaida ndogo, na rahisi, kuangalia kama kiambatisho tu ya gametophyte, ambayo ni kudumu kushikamana. Bryophyte sporophyte huishi kama vimelea juu ya gametophyte ya mama iliyozalisha. Picha iliyo hapa chini ni ya mwani wa kawaida, Entodon cladorhizans, unaoonyesha hatua zote mbili za mzunguko wa maisha. Entodon ni mwani wa kawaida kwenye magogo ambayo mara nyingi hutokeza sporofiti.