Bromus: A Deep Dive with Ferb Vu
The world of grasses is vast and often overlooked, but to me, it’s a source of endless fascination. Today, I want to delve into a particular genus that has captured my attention: Bromus, more commonly known as brome grasses, cheat grasses, or chess grasses.
These grasses, belonging to the Poaceae family, are found across temperate and cool regions of the globe. They are characterized by their spikelets, which are the basic units of a grass inflorescence. Each spikelet contains multiple florets, small flowers that are typical of grasses.
Why Bromus?
My interest in Bromus stems from their ecological and agricultural significance. Some species are valuable forage grasses, providing nutritious feed for livestock. Others, however, are considered weeds, competing with crops and native plants. This duality makes them a compelling subject for study.
A Diverse Genus
The number of Bromus species is a subject of ongoing debate among taxonomists, with estimates ranging from 100 to 400. However, the current consensus hovers around 174 distinct species.
Here are:
- Bromus aegyptiacus Tausch
- Bromus alopecuros Poir.
- Bromus andringitrensis A.Camus
- Bromus anomalus Rupr. ex E.Fourn.
- Bromus araucanus Phil.
- Bromus arenarius Labill.
- Bromus aristatus (K.Koch) Steud.
- Bromus arizonicus (Shear) Stebbins
- Bromus armenus Boiss.
- Bromus arrhenatheroides Baker
- Bromus arvensis L.
- Bromus attenuatus Swallen
- Bromus auleticus Trin. ex Nees
- Bromus ayacuchensis Saarela & P.M.Peterson
- Bromus benekenii (Lange) Trimen
- Bromus berteroanus Colla
- Bromus biebersteinii Roem. & Schult.
- Bromus bikfayensis A.Camus & Gomb.
- Bromus × bolzeanus H.Scholz
- Bromus bonariensis Parodi & J.H.Camara
- Bromus borianus H.Scholz
- Bromus brachyantherus Döll
- Bromus brachystachys Hornung
- Bromus × brevieri Chass.
- Bromus brevis Steud.
- Bromus briziformis Fisch. & C.A.Mey.
- Bromus bromoideus (Lej.) Crép.
- Bromus carinatus Hook. & Arn.
- Bromus caroli-henrici Greuter
- Bromus catharticus Vahl
- Bromus cebadilla Steud.
- Bromus ceramicus Ohwi
- Bromus chrysopogon Viv.
- Bromus ciliatus L.
- Bromus coloratus Steud.
- Bromus × commutatojaponicus Nyár.
- Bromus commutatus Schrad.
- Bromus condensatus Hack.
- Bromus confinis Nees ex Steud.
- Bromus danthoniae Trin.
- Bromus densus Swallen
- Bromus diandrus Roth
- Bromus dolichocarpus Wagnon
- Bromus × eburonensis (Nyman) K.Richt.
- Bromus elidis H.Scholz
- Bromus epilis Keng f.
- Bromus erectus Huds.
- Bromus exaltatus Bernh.
- Bromus fasciculatus C.Presl
- Bromus × ferronii Mabille
- Bromus firmior (Nees) Stapf
- Bromus × fischeri Cugnac & A.Camus
- Bromus flexuosus Planchuelo
- Bromus formosanus Honda
- Bromus frigidus Boiss. & Hausskn.
- Bromus frondosus (Shear) Wooton & Standl.
- Bromus gedrosianus Pénzes
- Bromus gracillimus Bunge
- Bromus × granatensis A.Camus
- Bromus grandis (Shear) Hitchc.
- Bromus grossus Desf. ex DC.
- Bromus × guetrotii A.Camus
- Bromus gunckelii Matthei
- Bromus × hannoverianus K.Richt.
- Bromus haussknechtii Boiss.
- Bromus himalaicus Stapf
- Bromus hordeaceus L.
- Bromus husainii P.Agnihotri & R.Yadav
- Bromus × husnotii A.Camus
- Bromus induratus Hausskn. & Bornm.
- Bromus inermis Leyss.
- Bromus insignis Buse
- Bromus intermedius Guss.
- Bromus interruptus (Hack.) Druce
- Bromus japonicus Houtt.
- Bromus kalmii A.Gray
- Bromus kashmirensis P.Agnihotri & R.Yadav
- Bromus koeieanus Melderis
- Bromus kopetdagensis Drobow
- Bromus kozhevnikovii (Prob.) Chepinoga
- Bromus × laagei Cugnac & A.Camus
- Bromus laevipes Shear
- Bromus lanatipes (Shear) Rydb.
- Bromus lanatus Kunth
- Bromus lanceolatus Roth
- Bromus latiglumis (Shear) Hitchc.
- Bromus lepidus Holmb.
- Bromus leptoclados Nees
- Bromus lithobius Trin.
- Bromus × litvinovii Roshev. ex Nevski
- Bromus macrantherus (Hack. ex Trab.) Henriq.
- Bromus macrocladus Boiss.
- Bromus madritensis L.
- Bromus magnus Keng
- Bromus mairei Hack. ex Hand.-Mazz.
- Bromus malyschevii (N.V.Vlassova) Chepinoga
- Bromus mango É.Desv.
- Bromus marginatus Nees ex Steud.
- Bromus maritimus (Piper) Hitchc.
- Bromus maroccanus Pau & Font Quer
- Bromus modestus Renvoize
- Bromus moellendorffianus (Asch. & Graebn.) Hayek
- Bromus moesiacus Velen.
- Bromus moeszii Pénzes
- Bromus morrisonensis Honda
- Bromus musadoghanii Yıld.
- Bromus natalensis Stapf
- Bromus nepalensis Melderis
- Bromus nottowayanus Fernald
- Bromus orcuttianus Vasey
- Bromus orientalis Behçet & Yapar
- Bromus oxyodon Schrenk
- Bromus pacificus Shear
- Bromus pannonicus Kumm. & Sendtn.
- Bromus parodii Covas & Itria
- Bromus paulsenii Hack.
- Bromus pectinatus Thunb.
- Bromus pellitus Hack.
- Bromus picoeuropeanus Acedo & Llamas
- Bromus pinetorum Swallen
- Bromus pitensis Kunth
- Bromus plurinodis Keng
- Bromus polyanthus Scribn. ex Shear
- Bromus porphyranthos Cope
- Bromus porteri (Coult.) Nash
- Bromus psammophilus P.M.Sm.
- Bromus pseudobrachystachys H.Scholz
- Bromus pseudolaevipes Wagnon
- Bromus pseudoramosus Keng f. ex L.Liu
- Bromus pseudosecalinus P.M.Sm.
- Bromus pubescens Muhl. ex Willd.
- Bromus pulchellus Fig. & De Not.
- Bromus pumilio (Trin.) P.M.Sm.
- Bromus pumpellianus Scribn.
- Bromus racemosus L.
- Bromus ramosus Huds.
- Bromus remotiflorus (Steud.) Ohwi
- Bromus richardsonii Link
- Bromus rigidus Roth
- Bromus riparius Rehmann
- Bromus × robustus H.Scholz
- Bromus × rosettiae A.Camus
- Bromus rubens L.
- Bromus salangensis Naderi
- Bromus sclerophyllus Boiss.
- Bromus scoparius L.
- Bromus scopulorum Chase
- Bromus secalinus L.
- Bromus segetum Kunth
- Bromus × segoviensis A.Camus
- Bromus setifolius J.Presl
- Bromus sewerzowii Regel
- Bromus sinensis Keng f.
- Bromus sipyleus Boiss.
- Bromus sitchensis Trin.
- Bromus speciosus Nees
- Bromus squarrosus L.
- Bromus staintonii Melderis
- Bromus stenostachyus Boiss.
- Bromus sterilis L.
- Bromus striatus Hitchc.
- Bromus suksdorfii Vasey
- Bromus sundaicus Ohwi
- Bromus syriacus Boiss. & C.I.Blanche
- Bromus tectorum L.
- Bromus texensis (Shear) Hitchc.
- Bromus timorensis Veldkamp
- Bromus tomentellus Boiss.
- Bromus tomentosus Trin.
- Bromus tunicatus Phil.
- Bromus tyttholepis (Nevski) Nevski
- Bromus variegatus M.Bieb.
- Bromus villosissimus Hitchc.
- Bromus vulgaris (Hook.) Shear
Identification Challenges
Identifying Bromus species can be quite challenging, even for experienced botanists. The differences between some species are subtle and can be easily overlooked. Key features to examine include the size and shape of the spikelets, the presence and length of awns (bristle-like appendages on the florets), and the hairiness of the leaves and sheaths.
Ecological Impact
Bromus species play a significant role in their respective ecosystems. Some, like smooth brome, are beneficial, providing forage and stabilizing soils. Others, like cheatgrass, can have detrimental effects. Cheatgrass, with its ability to thrive in disturbed areas and its flammable nature, has increased the frequency and intensity of wildfires in the western United States, threatening native plant communities and altering wildlife habitats.
Economic Importance
From an economic standpoint, Bromus species have both positive and negative impacts. Forage grasses like smooth brome contribute to livestock production, while weedy species like cheatgrass can reduce crop yields and increase weed control costs.
Future Research
There’s still much to learn about Bromus. Further research is needed to better understand the ecological roles of different species, their potential for invasiveness, and their response to climate change. This knowledge will be crucial for developing effective management strategies and ensuring the sustainability of our ecosystems and agricultural practices.
I hope this exploration of the Bromus genus has shed light on its complexity and importance. It’s a reminder that even seemingly mundane grasses can have a profound impact on our world. As I continue my botanical journey, I look forward to uncovering more secrets hidden within the world of Bromus.
