INTRODUCTION
MATERIALS AND METHODS
RESULTS AND DISCUSSION
Key to the species of Tripleurospermum in Mongolia
1. Plants perennial with rhizome; stems unbranched, scattered pilose below capitula; capitula solitary, terminal, 3–4 cm in diameter; corona with broad obtuse teeth ····················· ···························································· T. ambiguum (native)
1. Plants annual or biennial, without rhizome; stems corymbosely branched in upper 1/2, glabrous; capitula several to many, in an apical corymb, 2–3 cm in diameter; corona short, subentire ·············· T. inodorum (non-native)
Key to the species of Hordeum in Mongolia
1. Plants perennial; glumes subulate-setaceous, not lanceolate dilated at base.
2. Glumes much (usually more than 10×) longer than floret········································································ H. jubatum (non-native)
2. Glumes shorter to slightly longer than floret.
3. Lemma awns in medial spikelets up to 4 mm long; anthers in fertile spikelets 2.8–4.3 mm long ··································· ·························································································································································· H. brevisabulatum (native)
3. Lemma awns in medial (fertile) spikelets 5–12 mm long; anthers in fertile spikelets 0.7-2 mm long.
4. Stems with short-pilose nodes. Lemmas on outside studded with elongate spinules throughout surface; anthers 1.2– 2 mm long ··········································································································································· H. bogdanii (native)
4. Stems with glabrous nodes. Lemmas on the outside only in upper part with short spinules; anthers 0.7–1.2 mm long ·· ···························································································································································· H. roshevitzii (native)
1. Plants annual; glumes lanceolate dilated at base.
5. Spikes distichous: in each group of 3 spikelets only medial one bisexual and fertile, lateral ones sterile (underdeveloped or staminate); lemmas of medial spikelet with long awns ······································ H. vulgare subsp. distichon (non-native)
5. Spikes hexastichous: all 3 spikelets in each group fertile, with bisexual flower.
6. Lemmas at apex with long awn ······································································································· H. vulgare (non-native)
6. Lemmas at apex with tripartite appendage, its shorter lateral lobes deflexed downward, and large medial one spurlike, curved ··············································································································································· H. aegiceras (non-native)